A DECADE AGO, when I lived in Berlin, I would often detour from my daily run through Tiergarten, the city’s appealingly untended park, to visit certain buildings I felt drawn to for reasons I couldn’t name. These were largely (though not exclusively) midcentury dwellings — some neglected, others wildly overgrown — on or in the park that seemed to reify my sense of the city’s layered strangeness, of its mystery and opportunity for discovery. Even more than other European cities, Berlin is marked by the remains of all kinds of ideologies past, from the TV Tower in the vast main square, Alexanderplatz, a retro-future icon erected in the late 1960s by the East German government in a now poignant display of might, to the buildings the Nazis left behind. (Hitler never did fully realize his vision of a rebuilt Berlin as the capital of “Germania,” but the kind of neo-Classical bombast he had in mind is evident in the Olympic Stadium, which he commissioned shortly after he took power in 1933 and was completed in time for the 1936 Summer Games, and the limestone Tempelhof Airport terminal, which was constructed between 1936 and 1941 and, following the war, became a site of the airlift that sustained the city with food and supplies when Stalin blocked access to West Berlin.) All architecture conveys a set of narratives, histories and values for how best to live, and today’s Berlin, a jumble of tragedy and utopian ambitions past — and, these days, encroaching foreign investment — can feel like an especially dark choose-your-own-adventure story.
It has always been the Modernist buildings in the city’s former West that have fascinated and even moved me, from Le Corbusier’s Unité d’Habitation (an apartment building now known as Corbusierhaus) to the residential complex of Hansaviertel, just north of the park, which includes apartment towers designed by Walter Gropius, Alvar Aalto, Oscar Niemeyer and others. Both were the result of the International Building Exhibition’s Interbau 57, for which prominent architects of the era were invited to design residential housing in Berlin, just over a decade after the end of World War II. This, of course, was long before the money and glamour arrived, in those years of eerie stasis when West Berlin was a small enclave marooned within East Germany; the resulting buildings — inexpensive, socially attuned, beautifully rendered — were created in a burst of postwar idealism, helping to fill in the vast gaps in the cityscape and to house displaced people. Designed in keeping with the very principles Hitler had rejected, many of them by the visionary thinkers who fled the Nazis in the 1930s — including the former Bauhaus directors Gropius and Ludwig Mies van der Rohe — they communicate something powerful about the city’s vicissitudes, the troubling capriciousness of history.
Following reunification in 1990, Modernist residential buildings fell out of fashion in a rush to remodel and preserve prewar buildings in the city’s former East. Some of them began to seem a bit forlorn, or maybe just sleepy, in a freshly awakened city. (Another setback for Modernist architecture in Berlin was the decision, in 2003, to demolish the asbestos-filled Palace of the Republic, a bronze-windowed icon of ’70s architecture, and replace it with a replica of the Baroque-era Berlin Palace.) But by the mid-aughts, members of Berlin’s creative class began to settle in and refurbish these postwar buildings. Among them was Peter Heimer, a contemporary-art consultant and dealer who, in 2011, bought a home in the visionary German architect and design engineer Frei Otto’s little-known Ökohaus (eco-house) development — a multistory, greenery-covered townhouse complex located at the southern edge of Tiergarten, in an area historically associated with embassies, not experimental architecture. Heimer, 53, had the graciousness to accommodate a curious stranger when I wrote to him last fall and invited myself over to tour his home after I saw an image of it on a mutual friend’s Instagram. What, I wondered, was it like to live in this kind of design experiment? Could Otto’s Ökohäuser be one of ecotopian architecture’s early success stories?
In Berlin, the Ökohaus project remains something of an open secret. Completed in 1992, on land where the Vatican embassy once stood, the dwellings yield for much of the year to ruffled vines, vanishing completely from the casual onlooker — an almost absurdly lush, jungly break in the austere, ambassadorial streetscape. Their undoneness struck me as too deliberate to be a squat — the inhabited derelict buildings that were once a familiar sight in Berlin — but the varied exteriors were messy enough to suggest some kind of cooperative, countercultural living exercise. Through the overgrowth, one can see a hodgepodge of decontextualized styles and references — Cape Cod-style facades here, 1980s po-mo there; a lot of glass and wood and concrete, including futuristic-looking, glassed-in staircases snaking through the foliage; grass-covered roofs and concrete decks with metal fences trailing plants faintly reminiscent of Japan’s traditional hanging gardens. I could imagine Hansel or Gretel emerging from the green to open the gate. It was one of Berlin’s last remaining mysteries in a vast city that by then felt thoroughly discovered.
TO LIVE WELL in the city, more conscientiously, and more closely with nature: This has long been a preoccupation for postwar architects, one that Otto had thought much about by the time his project was commissioned for the second International Building Exhibition, Interbau 87, to be built on what was then an undesirable part of West Berlin in the shadow of the wall. (He had originally developed the concept three decades earlier, in a taller edition that was never built, for a site near New York’s Central Park; for much of his adult life, he lived with his wife and five children in a free-standing glass-and-wood Ökohaus of his own that he built in 1969 next to his atelier, in Warmbronn, in Germany’s southwest.) Raised near the Saxon city of Chemnitz in a family of artists and idealists — his mother named him the German word for “free,” her life’s guiding principle — Otto’s architectural studies were interrupted by the Nazi war machine, and seeing Germany in flames from his Luftwaffe plane inspired him to imagine a new kind of architecture that would be transparent, democratic, nonhierarchical and free. In a French P.O.W. camp, he also saw a practical need for temporary structures that could be improvised and flexible, as well as built simply and inexpensively: He understood the ephemeral nature of life, of the city, of nature, and was dismissive of monumental architecture, which he likened to gravestones.
Partly because Otto’s practice was often theoretical or collaborative — he worked with Shigeru Ban on the Japanese Pavilion in Hannover, Germany, at Expo 2000 and is best known for his lightweight cable-net and membrane constructions, including the roof of Behnisch & Partners’s 1972 Munich Olympic complex, its gleaming, tentlike canopy echoing the topography of the nearby mountains — he never became a household name, even after he won the Pritzker Prize in 2015, which was announced posthumously. And yet his influence is inarguable: By converting the destruction and horror of the 20th century into principles that continue to shape architecture today, he brought warmth and light to high-modernist ideals — for the engineering for Mies’s Neue Nationalgalerie in the 1960s, Otto suggested eliminating many of the internal pillars — and was inspired by structures found in the natural world such as crab shells, bubbles, spider webs or, in the case of the Ökohaus, trees. Norman Foster and Zaha Hadid have credited him as an inspiration, and one detects offshoots of his ideals in the work of younger architects like Sou Fujimoto and Neri Oxman. In contrast to the flamboyant postmodern statements made by many of his peers, Otto had a self-effacing, environmentally attuned approach that feels almost radically foresighted.
Even now, the Ökohaus concept sounds quixotic, even fanciful. Preserving the site’s mature chestnut tree (as well as gnarled wrought-iron fences and a bit of stone rubble, traces of the embassy that once occupied it), Otto designed three concrete, treelike skeletons, each composed of several trunklike columns with platform branches. Within this infrastructure, prospective owners would customize and build their own “nests,” putting into practice an idea — that everyone should have the freedom to create his or her own home environment — Otto shared with the late Yona Friedman, the Hungarian-French architect-philosopher who likewise questioned the role of the architect in society in his theoretical projects, which emphasized individual choice. Making these ideals (literally) concrete wasn’t logistically easy — there were a score of original owners, many of them architects and intellectuals themselves — but the project was a success, resulting in the complex’s characteristic patchwork of styles and materials. The third “tree,” designated for rentable social housing and owned by the city (it was sold off to a private investor shortly before Heimer bought into the complex), featured small townhouse-like apartments designed by Otto himself, who stacked small two-story residences, each featuring double-decker glass winter gardens, on the branches. (In total, there are 26 homes in the complex; each is roughly 1,400 square feet, with additional outdoor space in the form of private yards or hanging gardens for the upper units.) “At first, I said, ‘Oh, it looks like a kindergarten,’” jokes Heimer, who moved to Berlin in 1988 for architecture school and has witnessed the city’s dramatic shifts in fate. “And then I thought, ‘OK, this is the challenge.’ It’s about living with nature in the city. And in the end, it’s more about ethics, not aesthetics.”
THE SURPRISE, THEN, is just how beautiful this approach can be. In restoring the home (with the help of the architect Pierre Jorge Gonzalez, of the Berlin-based firm Gonzalez Haase), Heimer preserved Otto’s arrangement of rooms; most of the materials, which include oak, concrete and the kind of industrial white ceramic tile found in commercial kitchens and public swimming pools, are original. The lighting — dimmable halogen bulbs mounted on solid brass strips that run the length of the ceilings, which range in height from 9 to 11 feet — was upgraded for Heimer’s art collection: downstairs, a massive 1995 rubbing by the American artist Matt Mullican in bright primary colors; upstairs, a disc painting by the Danish artist Poul Gernes from the late 1960s. Just as Otto favored the juxtaposition of sunlight and shadows, Heimer gravitates toward the compelling contrast of pale tones and dark, warm textures. The dining-room floor and the staircase are lacquered black, setting off the white walls and vintage Berber rugs. A rustic dining table made of two glowing pieces of a single oak by Katja Buchholz, a German sustainable-furniture designer, is surrounded by cantilevered angular powder-coated aluminum chairs that were realized for Heimer by the Berlin-based Jerszy Seymour. The home flows so organically that it seems larger than it is: Downstairs is the open kitchen, winter garden and dining room; upstairs, Heimer’s spacious study occupies the space that was originally the main bedroom. Gonzalez redesigned an open space as a dressing area with built-in closets, adding a wall that separates it from the upstairs winter garden, where Heimer’s partner, the actor Christoph Glaubacker, grows Swiss chard, kohlrabi and tomatoes. Only in the upstairs bath, looking at the floor’s tile grid — which Heimer slightly reworked, inspired by the kind of grid systems utilized by the 1960s Italian architectural firm Superstudio, whose anti-consumerist ethos dovetailed with Otto’s beliefs — do I realize that the home’s footprint is a parallelogram: The rooms have no right angles. This was something of a headache for the tile setter, Heimer explains, as well as for Buchholz, who made the bookshelves in Heimer’s study, but it has the effect of eliminating the boxy feeling common to many Modernist dwellings; the home is clean-lined and bright but retains its nestlike Gemütlichkeit.
Over Kaffee und Kuchen in the downstairs winter garden, which he has filled with plants (a sculpturelike monstera, the delicate filigree of an asparagus fern) and furnished with red vintage chairs by the Japanese designer Kazuhide Takahama and a corn-yellow daybed he designed — a nod to interior color schemes favored by Frank Lloyd Wright, a key influence of Otto’s — Heimer calls my attention to the room’s exposures. Using a sundial-like instrument of his own design, Otto was able to precisely measure the movement of the sun in winter and summer and then orient the windows and rooms accordingly, so that each home would have a bright side and a shaded side, minimizing energy costs. The winter garden windows open electronically (also per Otto’s design) and look out onto verdant thatches of privacy-preserving bamboo and medlar; from his desk, Heimer faces the massive 90-year-old chestnut tree, its leaves blushing madly with fall color. “I respect nature much more, and the simple idea that you have to give things time to let them grow and to care for them every day,” says Heimer; before moving into the Ökohaus, he lived in an Altbau (pre-Modernist) apartment in Charlottenburg filled with meringue-like period plasterwork. In addition to the winter gardens, there’s a small grassy area where Heimer’s 14-year-old Vizsla, Ludwig (named after Mies), likes to lounge, as well as a small patio just big enough for a low-slung vintage concrete Loop chair by the Swiss designer Willy Guhl, who, like Otto, found liberation in doing more with less.
So, too, has living in the complex nurtured Heimer’s sense of community. As he tells it, the 70 percent or so of the original owners who remain, many of them now in their 70s, are esteemed by the newcomers for their role in maintaining Otto’s project. All are united by the architect’s larger ideals, both ecological and social: the belief that a fabulous life in the city can be low-impact; that individual freedom can blossom within a collective. As the forces of gentrification make urban life all the more tenuous for so many of us — one wonders what Otto would have made of Berlin’s increasingly Darwinist real-estate market, which has been pushing out the very people and ways of life that make a city thrive — this democratic mentality feels lamentably remote. The Ökohaus isn’t just an ecotopian fairy tale; it’s a model of flexibility and optimism, conceived in an era when we lived with less fear of the unknown and of each other, a time when we were still game and were open to ideas that spoke to more than the bottom line, back before we lost our belief in the possibility — via beautiful, innovative design — of a better common future.