Adaptive reuse for leftover urban landscape: ruins, remains, waste and monsters for an approaching genealogy of future

Purpose – This paper aims to explore the topic of adaptive reuse referring to urban open spaces into a more-than-human perspective. It underlines that dealing with heritage means being part of an inherent and ongoing process of transformation and so that reuse is inextricably an adaptive practice, constantly facing mutations, andthatadaptationisacoralpracticethatinvolvesdifferentkindsofusersandmakers,inclusiveofhumanand nothumanlivings. Design/methodology/approach – This paper looks at the lexicon of abandonment, in search of the more essential and intense meanings of words, and at some pioneering practices in Europe to comprehend the aesthetic and ethical implications of adaptive reuse of neglected landscapes. Findings – Processesofreuseinvolvemanydifferentcommunitiesofuserswhointurncontinuouslyredesign thesite,intoacomprehensive,coralandconflictingcollaboration,whoseresultsarenevergivenonceforalland arebothuncannyandbeautiful,scaringandmarvellous,likeamonster. Practical implications – Accepting the idea that humans are not the only users and makers of urban sites can widen the range of tools, methods and values involved in heritage adaptive reuse. Originality/value – This paper tries to widen the meanings of adaptation into a multispecies perspective. It intendstobroadentherangeofagentsthatcanbeinvolvedasusersandmakers,assumingamore-than-humanpointofviewthatisnotyetcommonlyapplied.

can be involved as users and makers, in a more than human perspective. The second part of this paper looks at landscape architecture practice to find clues of such a processual and multispecies interpretation of adapting reuse. It refers to cases of the last 40 years located in Germany, where peculiar historical situations have been creating the conditions for a wide experimental field of projects. In that field, the idea of adaptation sets new aesthetic and ethic categories for design, which arise from the intersection between biological, social, environmental, political and artistic issues, taking the figure of monster as a powerful metaphor of doubleness, openness and experimentation. So, this paper would propose two main statements. One is that dealing with heritage means being part of an ongoing process of transformation that can never be stopped and so reuse is inextricably an adaptive practice that is constantly facing changes and mutations. The other one is that adaptation is a coral practice that involves different kinds of both users and makers, inclusive of human and not human livings. Finding handholds in the lexicon À in search of the more essential and intense meanings of words À and looking at some pioneering practices in Europe are both ways to better comprehend the aesthetic and ethical implications of adaptive reuse of neglected landscapes and to understand their reasons and their rooting, in a sort of approaching genealogy of future.

A ruin is a movement
The word ruin is usually used to say a broken-down manufact, such a building, a construction, an object; thus, a ruin is typically a thing or, at least, a state. Nevertheless, its literal meaning says that a ruin is the action of falling, such as an avalanche is the action of sliding down; in Italian, the two words sound very close one to each other, we say rovina (ruin) and slavina (landslide), both telling a fall. So, a ruin is not a thing but a movement, an action, a happening, an ongoing mutation: a ruin is the performance of falling into the world and into time. Everything that exists is continuously falling, everything and everyone are continuously going into ruin. Everything and everyone are moving and getting transformed into something and someone different. This happens every single moment. I am the ruin of what I was yesterday and tomorrow I will be the ruin of what I am today. We are all ruins; the entire world is a ruin, because of a perpetual and ceaseless alteration, because of multiple occurring manipulations made by other livings and by not-living agents. Being in ruin means standing within a ceaseless metamorphosis which derives from never-ending agreements with the whole multiplicity of existences that we call world (Coccia, 2021a). Being in ruin means being continuously redesigned and remade. Being in ruin means endlessly passing away and being reborn. In these terms, being a ruin means being under design and under construction, inside a transitional movement to other states of existence produced by the interactions with other agencies. In these terms, conservation and restoration have no sense, at all. The only chance is adaptation to change, the only chance is design for being adaptive.

A remain is a judgement
Rudere is the Italian word to say remains. The expression 'ruderal plants', for example, comes from that. For the ancient Romans, rudera meant scraps; more precisely, they were the tiny pieces leftover from the making of a bronze object. They were the alloy that was not manufactured or used, which remained out of production. So, the difference of value between the used bronze and the leftover bronze is not a quality of the material itself but it is just the human manufacturing. What is wrought (man-made) is noble, what is rough (self-made, otherwise made, existing besides human crafts) is waste. What is used by man is valuable, what is neglected by man (but probably used by other livings) is worthless. This linkage between manufacture, use and value has a lot of consequences, not only in terms of economy, but even in terms of morals, due to the stigma falling on everything that is out of the production chain. For instance, manmade natureinclusive of agriculture, any kind of parks and gardens, even 'natural reserves' established by the humansis commendable, while the uncultivated nature, not by chance defined by a negative attribution, is just wasteland, it is inappropriate and unsuitable, according with aesthetics, ethics and functional criteria. This happens because we miss to consider that we are not the only makers and users of the places where we live and that the uncultivated land is curated by other livings, and it is used by other livings. Being a remain, a rudere, is never a matter of fact, it is just a point of view and a judgement.
Waste is a form of precocious design Waste is another interesting word. It means what has been refused following a selection. In Italian, we use the word scarto, with the same meaning of junk or scrap, that is residual staff, or residuo (leftover), which derives from the Latin verb residere with the meaning of staying and remaining, of not moving. As we already observed with ruin, even waste is not a thing or a state, but an action, a behaviour, a performative attitude. In Italian, the word scarto has even a different meaning. It stays for sudden movement, acceleration, swerve. So, it evokes the chance of opening new direction and producing a change. This double and conflicting meaningon one side staying and remaining, on the other one speeding up and veering À recurs even in another Italian word to say scrap: avanzato. It literally means leftover and exceeding, so it is a translation for waste. But it also means advanced, evolved, innovative, cutting-edge and avantgarde. Moreover, it is the past participle of the verb avanzare, which means moving forward, proposing and promoting. So, on one side being avanzato means remaining (lethargy) and on the other it means progressing (push and innovation). This implies that waste can contain advancement and that remains can give off future. This suggests that leftover landscape (paesaggi avanzati) can be a sort of forethought, that they can be forms of precocious design, which precede and proceed (Metta, 2022). This requires giving dignity to what is apparently out of use, out of functionality, out of purpose and looking at remains as advanced laboratories of cooperation with many other agents and willingness, with many other forms of utility and intentionality. This requires looking at waste in terms of the generation start, and not of the production end.

Ambiguity, coexistence and contradiction
This perspective on heritage could help to reframe the ethics and aesthetics of adaptive reuse of 'neglected' urban landscapes, calling us to review terms and ideas such as abandonment, decay, rebirth, users, nature, adaptation, agency and starting from the crucial statement that they all need to be put into mutual dialectics. These terms have all an interchangeable meaning, due to the point of view that we assume in turn: so, for instance, what does abandonment mean? Abandonment by whom? Reframing the implications of the meaning of these words calls us to accept the risk of ambiguity and misunderstanding, of ambivalence of values and assessments. It calls us to take the risk that sites neglected by the humans could have opposite qualities because of the needs of other users and the effects of other agencies, going out the alternative (this or that) and embracing coexistence and contradiction (this and that). In this perspective, a ruin can be a form of past and future, a leftover productive plant full of weeds can be the result of a failure and of a conquest, an abandoned lot can be useless and priceless; a wasteland can be uncanny and beautiful, natural and artificial, human and not human. Perhaps, the very essence of adaptation stays in the ways we could manage the landscape: Adaptive reuse for leftover urban landscape By using the term 'landscape', a dualistic, divisive understanding of nature and culture becomes impossible-instead, the focus is on the dynamic relations between humans, animals, plants, stones, water and all other elements in the world (Prominski, 2014: 6). According to this double-minded position, some topics arise. The first is that when we say re-use, we should specify who would be intended as the users, because the just human perspective is not enough to describe the wide range of possibilities that can be inscribed in the destiny of what we call heritage functionality. This caveat brings to reconsider the very idea of use and utility, and of their contrary, useless and impracticality. Thus, it requires to investigate the concept of users and makers, including in both the categories human and not human subjects. Furthermore, it asks to reframe the concept of abandonment and neglection, once admitted that the absence of the humans allows other forms of existence to develop, besides the traditional logic of rudera and remains. Another crucial question is the very idea of being adaptive, if we overcome the bare logic of multifunctionality and accept the more radical idea that during their life places can die and be reborn, being the same and nonetheless assuming completely different appearance and behaviours, such in the relation between a butterfly and a caterpillar (Coccia, 2021a). Finally, it implies that everything is constantly changing and that the only way to be adaptive is welcoming time and the transformations that it continuously produces.
Besides man-made nature Neglected landscapes, those which are no more productive and therefore forgotten by the humans, are very common in all the post-industrialised world. They are typically obsolete factories and infrastructures, whose reclaiming and renovation has become a recurrent topic for landscape architecture at least in the last 40 years, following different trajectories of approach. In Europe, Germany is the region where the underlined idea of contemporary ruins, remains and waste as a processual condition À a dynamic platform of potential interaction with a more than human perspective À has been developed in its earliest and boldest ways. Any attempt of outlining a genealogy should look at Kassel, where in the 70s, starting from diverse positions and with different backgrounds and goals, many scholars, teachers and practitioners gave a great contribution to reframe the idea of adaptive reuse in terms of a multispecies negotiation, widening the aesthetic and ethic horizon of landscape design. It was 1975, 20 years before Sol a-Morales wrote his famous statement about terrain vague (Sol a-Morales, 1995), when Dieter Kienast and Thom Roelly, who were students in landscape architecture at the University of Kassel, discussed their dissertation about the design of some open spaces in the Nordstadt district. Their proposal was based on a careful mapping of the landscape spots in the quarter. In addition to the traditional sites with gebaute vegetation [designed and implemented vegetation] À gardens, parks, boulevards, cemeteries and so onthey included abandoned lots with weeds and other wild or spontaneous vegetation, giving them the same dignity of all the other officially planned sites of the city. Kienast and Roelly described both the phytosociological features of those remains or wasteland, and the ways in which they were attended by local dwellers, recording that often, despite the unkempt and messy appearance of those places, they were successful, just because they offered new and unconventional opportunities for sociability and commonality. Eventually, Kienast and Roelly proposed to preserve those 'urban ruins' exactly as they were and even to make other designed open spaces become intentionally wild, leaving them deliberately undefined in form and function (Freytag, 2021). Their work completely rewrote the traditional criteria of urban design. From the point of view of aesthetic, they recognised that beauty was not only in 'manmade nature' and that the biological order of self-set spontaneous vegetation was able to add tasteful and aesthetically pleasing contents to a city otherwise carefully planned and tamed. From the point of view of ethic, they observed that apparently not-functional spaces could be nonetheless useful, just because at disposal of inventive, unexpected, experimental social rituals by people who used those places on their own accord and in accordance with the many other forms of life, plants and animals, occupying the same site. Kienast and Roelly's dissertation told that those places were relevant and worth to exist, establishing a new aesthetic and ethic paradigm.
Adapting to the unknown Kienast and Roelly's ideas resonate with the movement of political, social and artistic criticism that swept through Europe during the late 1960s and found in Kassel a special hotspot. We should consider, for example, the geographical and temporal coincidence with Documenta 5, titled Befragung der Realit€ at -Bildwelten heute (Questioning Reality -Pictorial worlds today), held between June 30 and October 8, 1972, in Kassel, under the artistic direction of Harald Szeemann. During the exhibit, the city was dotted with a constellation of diverse pictorial worlds of very diverse genre, level, language, letting the same visitors to decide for themselves what was art and what was not. It is reminded as one of the most controversial editions of the Documenta series. Its crucial idea is wondering whether the separation between official and counterculture arts has still any sense or not, exactly as Kienast and Roelly's dissertation argues whether the separation between sites which are designed by the humans (beautiful and useful) and wild sites (messy and useless) makes still sense or not.
Kienast and Roelly's work was directly influenced by the theories on dysfunctional spaces of Heinrich H€ ulbusch and Lucius Burckhardt, both professors at the University of Kassel during those years. Burckhardt called them 'no-man's-land': No-man's-land À this is where Schorsch lit his homemade rocket and Anne was kissed for the first time. No-man's-land does not exist, at least not in any decently planned city. No-man's-land is a product of planning: without planning, there is no no-man's-land. But if ever planners realize they have planned a no-man's-land, then its end is nigh. Then even its name is changed. As of then it is called 'a dys-functional zone.' But this does not yet bother Schorsch or Anne. They are upset only when urban planning teams burn down the bushes, level the banks of the stream, periodically mow the lawn, or install a public seating area and barbecue (Burckhardt, 1980, p. 126).
No-man's land is the equivalent of terra nullius, the formula used by the Europeans during the Great Explorations centuries to call those lands that, according to the colonists' foreign and extractive gazes, appeared uninhabited and unstructured À dysfunctional, Burckhardt would say À because they differed from the colonists' homeland, while on the contrary they were structured and inhabited by other human and not-human society. Diversity, alterity, being out-of-the-ordinary, not-conforming are all qualities that even today continue to create suspicion, in both aesthetical and ethical sense, and that are typically tamed with back-toorder policies and actions. In terms of adaptation, they are typically said unsuitable, inappropriate, unfitting, ill-suited, and unfortunately the question with them is usually how to adapt those sites to the average paradigm of beauty, utility, and morality, instead of catching the chance of new opportunities coming from adapting our habits to such unknown conditions.

Celebrating otherness
The presence of Peter Latz as professor of landscape architecture at Kassel in those same years (1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983) is further evidence of the crucial role of Kassel in the 70s for the development of a peculiar new attitude in dealing with remnants and apparently out-of-use sites. Indeed, the connection between the intellectual atmosphere of that university and his approach to the Emsher Park design of a few years later (1989)(1990)(1991) can be assumed more Adaptive reuse for leftover urban landscape than probable. Latz's project for the former Thyssen industrial site in Duisburg is a pioneering case study because it practiced the idea of respecting, celebrating and even boosting the presence of the spontaneous vegetation that, during the downtime of the factory, had colonised the once productive industrial plant. Other than human agentsintended both as designers and as usersare recognised as worthy and properly included within the environmental, functional and expressive systems of meaning proposed by the project, with a flagrancy perhaps unprecedentedly comparable. The theme of the transformation of former industrial sites into public parks was not new, but it was typically developed in terms of emphatic narrative of the memory of the industrial past through the transformation of the cleansed remains into contemporary shiny monumentslet consider, for example, the Gas Work Park in Seattle, designed by Richard Haag 15 years earlier (Way, 2015). On the contrary, in the Duisburg park Latz establishes a conspirational dialogue between the new human uses of the site (didactics, leisure, sport and tourism) and the different forms of life that in the meantime had already started to transformto adaptthe site after the stop of the industrial activities: this is what makes Latz's park a ground-breaking case, able to bring into practice the approaches arising in Kassel in those crucial years. Latz's project welcomes and emphasises the ongoing transformations carried on by the vegetation, the water, the climate and many other environmental agents, which inevitably have impacts of regeneration as well as consumption. From the time of its first opening, the different stages of active transformations, typical of secondary successions, have been revealed and valued; the richness of the communities of newly established pioneer plants expresses the heterogeneity of the variously toxic soils, the presence of water, and the exposure to an abrasive atmosphere; spontaneous prairies of wild perennial grasses and shrublands are kept close to intentionally designed plantations of groves and gardens, with uncanny combinations of pleasant and disturbing elements, regeneration and decay.
Our new conceptions must design landscape along with both accepted and disturbing elements, both harmonious and interrupting ones. The result is a metamorphosis of landscape without destroying existing features, an archetypal dialogue between the tame and the wild. The image of nature can be made of the 'untouched' and the 'built' (Latz, 2000, p. 97).

Mutual tampering
Adaptive reuse has plural and different meanings in the Duisburg Park. From the human side, it is adapting the once industrial structures as devices for sports and leisure: they are just secured and then made available for inventive use by the all-ages people who visit the park. From the plants and animals' side, it is adapting to live in a man-made habitat and use it for their own needs, both biological and social. From both the human and not-human beings' side, it is adapting to live together, sharing the same space and the same time, continuously negotiating their mutual relations. This produces a deliberately undecided situation, open to many different and always temporary results, inspired by an ethic of cooperation and not hierarchical arrangement. This produces an aesthetic of dynamic settings, which constantly transform with the recurrent and cyclical interchange of seasonsinclusive of both the life rhythms of plants and the human habits of outdoor livingand with the evolving succeeding of growing and passing away. The novelty and strength of this project lie in recognising the creative potential of not-human livings and in assuming intentional looseness (Smithson, 1970) as a proactive transformative opportunity.
This approach to heritage tells us that not-human agents can transform a site, reuse and reshape it, and give it new meanings and values. This means that eventually nature does not exist as that certain idea of an untouched realm, because everything is continuously made and remade by never-ending processes of generation and degeneration. So, everything is an artefact, realised by many authors, inclusive of humanity. The entire planet is totally artificial, in every thickness of its bowels and atmospheres, because it is the outcome of continuous alterations. Therefore, nature does not exist as a kind of zero degree of the world, because every form of life refines the space where it inhabits, gives it form by a relentless manipulating. So, everything that exists is invariably artificially made, used and reused in a fatally adaptive way. Nature does not exist as a primal condition biologically determined, since the whole planet derives from transformative processes operated by multispecies subjects: the planet is a huge, choral garden where we cultivate each other (Coccia, 2021b). This kind of approach states and reclaims that what is commonly called 'nature' has design skill and will, attributes that we often persist in considering only human (Rainer and West, 2015). Experiences such as the one in Duisburg demonstrate that an intermediate path between fatalism/determinism À which celebrates the disempowerment of the human species from the salvific remedies of nature À and supremacy À which recognises beauty, utility, and efficiency only to man-made landscape À is possible and practicable. Humans and nothumans are called to interact and collaborate and to both use the site adapting one to each other, because life, in all its biological, aesthetic and social issues, is nothing but an incessant action of mutual interference, of continuous mutual tampering of every living form, on itself and on others.

Accidental gardens
Berlin is another crucial spot of this genealogy. There, the 'advanced landscape' of remains are called brachen (fallow, idle). Their diffuse presence into the city is largely related to the city's peculiar post-World War II history, when Berlin was first dotted with rubble and then crisscrossed by forbidden lands along the 'death strip'. Indeed, soon after the downfall of the Mauer, the once 'death strip' became a sort of suspended site, waiting for a not predictable human future and meanwhile inhabited and reused by many other livings, mostly pioneering herbs. Another peculiar fact of Berlin is the disuse of many rail headstations. During the Cold War, all the station were under the sovereignty of the DDR which progressively abandoned the ones in the West part of the city. In all those sites, sorts of 'accidental gardens' gradually and spontaneously appeared, producing an extraordinary interweaving in which the natural history of the city (not-human heritage) overlaps with the events of the broader international geo-political context (human heritage, material and immaterial). So, in the brachen we read the historical becoming of Berlin, as a biological fact and at the same time as a social and economic construction (Gandy, 2022). It happens all the time, everywhere, but Berlin is one of those singular places where this extraordinary obviousness manifests itself with absolute flagrancy, with the power of a revelation.
Herbert Sukopp is among the protagonists of this story. Having been working at the TU Berlin since the late 1950s, he is unanimously considered one of the eminent pioneers of urban ecology and often referred to as the founder of the so called 'Berlin School of Urban Ecology' (Kowarik, 2020). Sukopp served as head of the Institute of Ecology at the TU Berlin until 1994, when he was replaced by Ingo Kowarik, and he dedicated his entire work to found urban biodiversity studies. In the same years of the before mentioned teaching of Peter Latz in Kassel, of the Kienast's dissertation at the same university and of the exhibit Documenta 5, Sukopp's comprehensive work Die Großstadt als Gegenstand € okologischer Forschung (The Big City as an Object of Ecological Research) was published in Berlin: it was 1973 and his book is considered the birth of the 'Berlin School of Urban Ecology', focussed on the peoplenature intersection and on how to integrate and improve the presence of many forms of life in urban environments. In his research, Sukopp observed all the land-use types within the city, aimed by the clear intention of recomposing any division between nature and city and of Adaptive reuse for leftover urban landscape looking at humans and not-humans as interrelated subjects in the same community of 'users & makers'. He found his ideal research field into the urban ruins, the remains, and the wasteland, properly because his attention was not focussed exclusively on the conservations of the species, but on the ecosystems' adaptability and on the chance to recur to spontaneous vegetation as an opportunity to qualify several urban sites, even in educational and social terms.
Organisms and biological communities should be conserved to allow people direct contact with the natural elements of their environment. Only such open spaces can lead to the experience of natural beauty which permits coexistence between a nature existing in its own rights and people who are free to determine their own actions in this space (Sukopp, 1997: 279).

Monsters
Sukopp recognised the important role played by landscape architecture to support the efforts of the ecologists. Their joined positions helped to overcome the idea that conservation, adaptation, and design are separated fields, as well as to overcome any division between concerns for plants and animals and concerns for humans, as well as to imagine and practice a deep and effectual collaboration between all the diverse communities settled in the city: Natural scientists and landscape architects are playing an important role in protecting nature and reintroducing it into cities. (. . .) Landscape architects have helped to elevate nature conservation to a strategic planning level and to make it part of political thinking (Sukopp, 1997: 266). Indeed, this kind of approach inform many projects that have been implemented in Berlin over the beginning of the XXI century, mostly dedicated to the adaptive reuse of neglected infrastructures sites. Gleisdreieck Park designed by Atelier Loidl (2011), S€ udgel€ ande Nature Park conceived by Ingo Kowarik and Odious (1999), Nordbahnhof Park designed by Fugmann and Janotta (2009) are all samples of reclaiming and reusing neglected rail stations, which have been reintroduced into the active cycles of the city while preserving the wild connotation gained during the time of their interdiction. Likewise, Adlershof Park designed by Gabi Kiefer (1996) and Tempelhofer Feld (2010) have recovered two former airfields, with the same kind of aesthetic and ethical tension toward a more than human adaptation. Some of them deliberately keep the presence of wild habitat that spontaneously developed during the sleeping years of those sites. It is the case of the S€ udgel€ ande Park, where a network of narrow gangways allow people to visit the park without disturbing the wood succession; of the Adlershof Park, whose core is a moorland, grown on the previous airfield, even thanks to the cuts in the asphalt introduced by Kiefer's project to boost the arrival of pioneering weeds; of the Nordbanhof Park, where most of the areas are fenced to suggest people to not go there and allow the wasteland to freely become a grove. All these cases are heirs of the groundbreaking ideas of Sukopp, who gave a great support for recognising the dignity of sites settled by communities other than human: The traditionally developed system of parks and green areas can be expanded by a system of existing, ecologically functioning areas, which have not yet been 'planned': areas resulting from war damage or demolition which are spontaneously settled by animals and plants (Sukopp, 1997: 278).
Perhaps the best way to describe this kind of adaptive landscape is to recur to the metaphor of monsters. I mean those mythological characters which are the fusion of human parts (typically the head and the bust) with parts taken from animals or plants, like Sirens, Sphinxes, Angels, Fauns, Centaurs, Spider Man. Monsters are hybrids between human and not human beings, and they incarnate the coexistence of different forms of life in their own body.
They are more than human and are uncanny: they are attractive but at the same time they frighten and scare, producing an ambivalence which works on both the aesthetic and ethic level. Monsters could be beautiful and seductive, but their appearance is completely out of standards, weird, anomalous and abnormal. Monsters' behaviours are often unpredictable and for sure out of average codes and expectations, they could be gentle and benign, but suddenly could become furious and dangerous. They typically have superpowers and can do things not allowed to 'normal' beings. Monsters are transgression and overcome the limit of ordinary life. Monsters are a matter of design, just because they do not follow any 'rule of nature', they should not exist according to what we call 'nature', so they are a product of invention, they are a novelty, something unheard and unseen before, they are a form of future. Therefore, the ancient Romans use monstrum (monsters), with portentum (marvels) and prodigium (prodigy) to preannounce and divine the future. Again, the etymon helps us: the word monster comes from two Latin verbs, one is monstrare, that is to reveal and make visible, the other is monere, with the meaning of warning. Therefore, future is fatally monstruous: The monster is also that which appears for the first time and, consequently, is not yet recognized. A monster is a species for which we do not yet have a name, which does not mean that the species is abnormal, namely, the composition or hybridization of already known species. Simply, it shows itself [elle se montre] À that is what the word monster means À it shows itself in something that is not yet shown and that therefore looks like a hallucination, it strikes the eye, it frightens precisely because no anticipation had prepared one to identify this figure (Derrida and Weber, 1995: 386). In this sense, monsters recall the idea of waste/advanced landscape as precocious future or precocious design that we suggested before. Then, due to their hybrid condition between human and not human, monsters embody the very idea of transformation, as if their appearance were the halfway of a moult or, more generally, of a mutation. In this sense, monsters recall the idea of movement, action and perennial transformation that we underlined before as the essential meaning of ruins. Finally, just because monsters are the absurd encounter of human and not human, they put us in trouble about judging what has value and what has not, if, as we recalled before about remains, we continue to think that only man-made sites or man-made nature is valuable, that only what serves human utility has dignity to exist.

A monster in Berlin
The Tempelhofer Feld is one of the most successful parks in contemporary Europe. Used as an airfield since 1883, it became an aerodrome for the newly founded Deutsche Lufthansa in 1926. From 1936to 1941, the National Socialist government built there the Ernst Sagebiel's famous gigantic terminal and established there the only forced labour camp in Berlin, for political prisoners. During the blockade of Berlin in 1948-49, the Allies set up there an air bridge with the western part of the city. The airport was stopped and closed in 2008 and soon after a design competition was announced to transform it into an urban park. Meanwhile, the Berlin governance took the seemingly harmless decision to open its gates and let people use it. Soon and unexpectedly, Tempelhofer Feld became one of the most popular parks in Berlin, a completely improbable encounter between an airport facility À whose components remain today entirely intact, from signage to lighting, runways and parachutes À and the rituals, behaviours, and practices typical of a leisure-time public park. A monster, indeed. It is an unheard-of place, 386 hectares of pure heterotopy, with a very high rate of wonder, because of both the unimaginable vastness, which is uncommon and exciting to find within the dense city, and for the excitement of being allowed to take possession of a previously forbidden place. It immediately appeared as an irresistible urge to invention.

Adaptive reuse for leftover urban landscape
The success has been such that in 2014 Berliners organised a referendum to vote on the implementation of the new park designed by Gross. Max, who in the meantime has won the contest, and the response was to keep it as it was. Meanwhile, various plants and animals have chosen the site as their own home and today about 80% of the former airfield is an important habitat for several red-listed birds, plants, and insects. The skylark (Alauda arvensis), a migratory species now quite rare in Germany, is among them. Each year, from the end of March to July, the areas between the two air tracks, where the birds make their nests, are closed off to humans; special wooden raised seats, placed just out of the temporary fences, allow people to sit and watch the meadows from above, observing the birds' movements without disturbing them. In August, when the larks have moved to other regions with a milder climate, and the fences have been removed, licenced farmers are called to mechanically mow the meadows in exchange for the right of haymaking. They took a few days for mowing, going quite slowly to allow the communities of insects inhabiting the grasslands to gradually move elsewhere. The bales of hay are then left to dry on site and are often used by Berliners as very comfortable bedding for resting in the park and catching the last summer sun. In the following months, the growth of the grasses is limited by the grazing of sheep and horses, which were chosen from flexing populations and brought into the park under the supervision of authorised breeders. This activity is compatible with the rarefied presence of humans in the colder months and advantageous in environmental terms: the animals, while grazing, conduct a selective and extended-over-time control over the herbs' growth, unlike the mechanical mowing that inevitably affects all grassland species and produces a sudden change in the microclimate. In addition, animal droppings attract insects, which in turn attract birds: here the cycle restarts, with larks and people coming back in early March. In this park, not-human livings are intended as users of the site and their protection does not imply the irrevocable and totalising separation from the humans. A covenant of commonality is established, through the scheduling of activities that allows the coexistence of several species, proceeding by temporary and partial interdictions, in accordance with the biological and social rhythms of all the species involved. This park is a place where different actors, each with their own needs and forms of freedom, conventional or inventive, can share the same space within partial temporal shifts. It is waste, it is future, it is marvellously monstruous.

Species at play
Urban parks have always been a place where different desires meet, as well as a platform for dealing with social conflicts, which otherwise tend to be avoided through the separation of functions and actors. What is new about these examples is that social conflicts no longer refer to the human community alone, but they become inclusive of a wider plurality of non-human inhabitants and users. Another novelty is that these inhabitants and users are given competence in the making of space: they no longer have an exclusively ecological value, nor a decorative value, as in the long tradition of the European parks that reproduced À I would say portrayed or depicted À wildlife scenes within the city, keeping them under human control, in ethical (behaviours) and aesthetical (appearance) terms. These inhabitants and users are also considered co-authors of the project, in an extended dimension of design. In these cases, adaptive reuse requires an expansion over time and in the number of actors involved in. It is a matter of accepting that we do not have full control over the formal and functional outcome of the project, since it is subject to transformations resulting from collaboration with other engaged agents. The idea of the 'open work', coined by Umberto Eco (Eco, 1962) just a few years before the 1970s when the Kassel and Berlin experiments began, is fully realised here; it is the idea that the fate of the site inherited from the past depends not only on the conscious technical and creative competence of the designer, but also on the interactions with human visitors, plants, animals, with every form of life, even the most minuscule, the climate, the waters and the soil. This means understanding the adaptive reuse of such places as 'room of possibility' (H€ außermann and Siebel, 2002), taking a cue from the psychoanalytic category of 'potential space' (Winnicott, 1971), which lies between a parent and a child, when the former allows the latter to discover his or her independence within the set limits. Indeed, this kind of adaptive use does not mean that the places of urban ruins, remains and wastelands are embedded within rule-based design horizons that offer the possibility of different plausible rewritings, exactly as in a game in which, despite knowing the rules or precisely because we know the rules, we continue to play because we cannot predict in advance the outcome of the game.