But the Aaltos’ choices of material and design weren’t just aesthetically fashionable. “The main purpose of the building is to function as a medical instrument,” Hugo would later write. Tuberculosis was one of the early twentieth century’s most pressing health concerns; each element of the Paimio was conceived to promote recovery from the disease. “The room design is deter­mined by the depleted strength of the patient, reclining in his bed,” Aalto explained. “The color of the ceiling is chosen for quietness, the light sources are outside of the patient’s field of vision, the heating is oriented toward the patient’s feet.” (The combination of cold feet and a feverish head was seen as a symptom of the disease.) Broad daylight from the windows as well as the terraces, where patients could sleep, was part of the treatment, as sun had been proved effective at killing tuberculosis bacteria. At the sanatorium, the architecture itself was part of the cure.

Much of modernist architecture can be understood as a consequence of the fear of disease, a desire to eradicate dark rooms and dusty corners where bacteria lurk. Le Corbusier lifted his houses off the humid ground to avoid contamination. Adolf Loos’s ultra-boxy Villa Müller in Prague, from 1930, included a separate space in which to quarantine sick children. Architects collaborated with progressive doctors to build other sanatoriums across Europe. “Tuberculosis helped make modern architecture modern,” the Princeton professor Beatriz Colomina writes in her revisionary history “X-Ray Architecture.” The industrialized austerity of Ludwig Mies van der Rohe or Marcel Breuer “is unambiguously that of the hospital,” the empty white walls, bare floors, and clean metal fixtures are all “surfaces that, as it were, demonstrate their cleanliness.”

As extreme as the aesthetic of modernist architecture seemed in the early twentieth century, people could at least be reassured that it was safe. A character in Thomas Mann’s novella “Tristan,” from 1903, described a “long, white, rectilinear” sanatorium for lung patients: “This brightness and hardness, this cold, austere simplicity and reserved strength . . . has upon me the ultimate effect of an inward purification and rebirth.” A tuberculosis vaccine began to be used on humans in 1921, but the association between modernism and good health stuck; the austere sanatoriums were marketed as palliatives for mental illnesses, too.

Quarantine makes all nonessential workers more intimately acquainted with the confines of their homes. We know everything about them, especially their flaws: the lack of daylight in one room, the dirty floor in another, the need for an extra bathroom. Space is all we have to think about. For architects, it’s a soul-searching exercise, especially if you happen to live in a home you outfitted for yourself.

The architect Koray Duman lives with his partner and their sixteen-month-old child in an apartment he designed, in the Lower East Side. Quarantine has led them to grow exhausted with the things they keep in the space, even though—with the exception of toddler accessories—they are relatively few. “You look at every detail of things. They limit you. If you have less you feel like you are more free, in a weird way,” Duman told me. Sustained scrutiny can breed discontent. Over the past two months, “interior designers got very busy,” he said. “People are, like, ‘I hate this space.’ ” Spending so long in one place might require an environment that can change more freely so that we don’t get bored. Usually a wall is static; “I don’t know that that’s necessary,” Duman said. “If it was on wheels, imagine how much fun you would have.”

Florian Idenburg and Jing Liu, a couple and the principals of the firm so-il—which has designed art museums, housing developments, and pop-up projects like the tent for the Frieze Art Fair—have been staying in their home, near the Brooklyn Navy Yard, with their two young daughters. It’s a bright white-walled duplex with open-plan common spaces. “Luckily, both our girls have their own rooms with thick doors,” Idenburg said. The arrangement comes in handy when the children have video-chat school sessions at the same time. Acoustic divisions have become more important while the family is crammed in together all day long, Idenburg noted. “The loft, the New York City typology, seems to be not the romantic thing at the moment. Everyone’s on Zoom calls.” A lack of privacy or the chance to move to a different room is harder to bear when bars, cafés, and stores can’t offer an escape.

Confronting the limits of their own home has made Idenburg and Liu rethink how they approach designing spaces for clients. “We don’t necessarily see this as the end of the world; we should not overreact,” Idenburg said. “But, subconsciously, people will really take it into account as they assess their home in the future.” Seeing any new space, in the midst of the pandemic, we quickly imagine what it would be like to be trapped there for months. During quarantine, so-il has been designing a residential project in Brooklyn with thirty units in a twelve-story building. They updated the apartment schematics to reflect pandemic anxiety: the kitchen, the dining room, and the living room are all separable instead of flowing together; the bedrooms are spaced apart, for better acoustic buffering as workspaces, and include more square footage for desks; and the architects are aiming for thirty per cent exterior space, with varied outdoor options. “It’s the importance of being able to get out,” Idenburg said. “Not just to cheer health-care workers but also be outside of the ecosystem for a little bit.”

Interior design reflects what we think represents an ideal of domesticity. From Versailles to President Trump’s baroquely gilded penthouse in Trump Tower, it is a mirror for the anxieties of a moment. “Each age demands its own form,” the Bauhaus architect Hannes Meyer wrote in his 1926 essay, “The New World.” “Ideally and in its elementary design our house is a living machine.” In the twentieth century, Meyer argued, “architecture has ceased to be an agency continuing the growth of tradition or an embodiment of emotion.” It was instead to be cold, functionalist, efficient. The same year, he arranged a single ideal room, which he called the Co-op Interieur, for the modern worker, envisioning not just an individual dwelling place but a template for an entire civilization. It was a bare box that held a cot, a gramophone on a table, a small shelf, and two chairs that could be folded up and moved. The whole assemblage was endlessly scalable and mobile, fit for the sweeping wave of technological globalization that Meyer observed in his essay. It’s also the last place you would want to be quarantined.

Architects have long been preoccupied with the concept of “existence minimum” or “the minimum dwelling,” as the critic Karel Teige titled his 1932 book. Teige proposed, to solve housing shortages, “for each adult man or woman, a minimal but adequate independent, habitable room.” The idea got an update with the Japanese Metabolist movement in the nineteen-sixties, which envisioned buildings that would expand and contract based on the needs of a city. Tokyo’s Nakagin Capsule Tower, by Kisho Kurokawa, one of Metabolism’s few built structures, is a series of individual boxes set around central spires, each containing what one person needs to live, at least for a brief period: a circular window, a television, a stereo, a desk, a bed, shared showers. The grand vision didn’t pan out; today, Nakagin is under constant threat of demolition, and the apartments now exist more as works of art.

Existence minimum has been on the mind of Paola Antonelli, a senior curator at the Museum of Modern Art’s department of architecture and design. On March 13th, she was called into the museum with the rest of the curatorial staff and given a few hours to pack all the books she needed for two months. Ever since, she’s been in her apartment, relying on a tripod for Zoom calls, a yoga mat for exercise, and excursions outside on Citi Bikes. Existence minimum suggests the least you need to feel comfortable in a space. For twenty-first-century city dwellers, that quantity has expanded over time, from Meyer’s bed, chairs, and phonograph to the mobile suite of accessories we carried with us everywhere pre-pandemic, as on a commute: headphones, smartphone, laptop, charging cords. Together, it formed a kind of “existence maximum”: as much as possible in as small a space as possible. “I have a bubble of personal space that is metaphysical, that is bigger than the physical space around me,” Antonelli said. “I can be squeezed in a subway car and I still have my world.”

Neither existence minimum nor existence maximum quite works at the moment. Personal spaces need to be both virtually connected and physically enriching even in the midst of social distancing—not the clean, white, anonymous smoothness of contemporary minimalist modernism but a textured hideaway, like an animal’s den, full of reminders that the rest of the world still exists, that things were once normal and might be again. We have to be able to hibernate.

Covid-19 calls for prophylactic design. Masks and gloves barricade our bodies like a second skin. Taped circles spaced six feet apart make sure we don’t contaminate others while standing in line at the grocery store. “Tape is one of the greatest materials in architecture,” Idenburg said, with a laugh. Other ad-hoc strategies have emerged as more businesses reopen. A Dutch restaurant built greenhouse-like glass booths around its outdoor tables to shield diners and waitstaff from each other. A German café tested out hats with pool noodles attached so that guests would know not to get too close to one another. A casino in Florida installed a thick sneeze guard of plastic on its poker tables, with clearance on the bottom for players’ hands.

It all amounts to a life-size infographic: you must remain this far apart. “If you want to change those habits of being close to people, we need to have very clear guidelines,” Jeroen Lokerse, the managing director of the Netherlands for the international real-estate conglomerate Cushman & Wakefield, said in a call from his home in Amsterdam. “Visualization is key to make sure people feel safe.” On March 25th, Lokerse had a meeting with the Dutch minister of economic affairs and the secretary of state about a relief plan for the retail sector. He drove back to his empty office and started wondering what could be done to make it safe for what the government was calling “the 1.5-metre society.”

The result was “the 6 Feet Office.” Carpet tiles demarcate six-foot black circles around every desk in the open floor plan. Extra chairs, positioned outside of the circles, facilitate conversation among colleagues. Conference-room chairs have been thinned out, and closed spaces must be exited clockwise, in unison, so that co-workers don’t bump into each other. “Hotdesking,” or the sharing of one desk by multiple workers, is made possible with disposable paper desk pads, on which a worker sets her laptop or keyboard and mouse when she arrives.

Cushman & Wakefield is slowly testing the 6 Feet Office design at its Amsterdam office, which used to hold two hundred and seventy-five people but now only has seventy-five at a time. As the lockdown lifts, Lokerse expects to start with twenty-five per cent of employees back at the office, but as more workers come back they’ll have staggered start times to avoid overcrowding on public transportation, and thirty-per-cent fewer desks over all. Bruce Mosler, the chairman of global brokerage at Cushman & Wakefield, noted that office spaces were already feeling too crowded before the pandemic and had started to limit crowding, a trend that is now accelerating. “We got carried away in the over-all densification process, in the effort to be as efficient as possible,” he said. “We went a bit too far. This is going to change that.”

One refrain of the quarantine is that at least it will have the benefit of killing off the much-maligned open office. Unfortunately for workers, companies might adapt before the template can be vanquished. Cushman & Wakefield’s circular floor tiles are low-cost and can be installed within forty-eight hours. Lokerse also has a surveillance program in mind to make sure that the guidelines are followed—there will be virtual walls, if not physical ones. Beacons will track the movements of workers’ phones, and the company tested but decided against using an app to signal when an employee moves within six feet of someone else. (Subtler than a pool-noodle hat.) Lokerse said that, should the company change its mind on the app, workers will be asked to join such tracking measures “voluntarily and anonymously.”

The architect Deborah Berke runs an eponymous firm, in New York; it’s known for a flavor of contemporary modernism that is clean but also contextual. In thinking about designing for the pandemic, Berke has looked to the example of spaces designed for the deaf, like Gallaudet University, in Washington, D.C. Such spaces need good lighting for signing or lip-reading, and devices like flashing lights to let people with hearing impairment know when someone has entered a room. We’ll have to be hyper-aware of the infrastructure of cleanliness, she told me: “Are people taking their shoes off at the door? Are coat closets big enough and far away enough? Is there a place by the door where you wash your hands?” Le Corbusier solved the last problem by installing a freestanding sink in the entryway of his Villa Savoye, from 1931.

Instead of replicating the old hygienic vacuum of modernism, Berke has been inspired by the vernacular devices that she notices popping up, the lines and barriers that individuals improvise from whatever’s at hand—plexiglass walls, shower curtains, or taped-together garbage bags that protect cashiers. Hula hoops help children stay apart in parks, and athletic trainers are using scaffolding as group pullup bars. “People are becoming, if not architects, the craftsmen and makers of safe spaces,” she said. “I don’t want us, the world of design professionals, to lose some of the positives, the democratization that’s coming out of some of this.” In architecture there’s always the temptation to seek a stable solution, the perfect design that will solve a problem forever, beyond the reach of human foibles. Such was the faded dream of the Bauhaus: a universally perfect space for all people, repeated around the world, imposed from a privileged position upon those with presumably worse taste. The better designs might be those that evolve from the bottom up as we all figure out our post-pandemic routines. Face masks are already presenting a democratized aesthetic. They all look different—patterned handkerchiefs, repurposed T-shirts, or celebrity-branded numbers from the Weeknd—but they all accomplish the same thing.

Quarantine turns us into explorers of the familiar. The young architect Ilias Papageorgiou moved from New York back to his home town of Athens, Greece, a year ago to start his own firm. (He used to be a partner at so-il.) Papageorgiou first left when he was eighteen; returning has given him a new experience of the city, particularly during quarantine, which he is spending with his wife and son in an apartment with a rooftop terrace, in the city’s downtown. When I spoke with him, the constant birdsong was loud enough to hear over the phone, an auditory postcard of sun and blue sky. “I’m feeling like I’m discovering a place,” he said.

Athens is laid out for cars; in the absence of workers commuting, the city is performing a different role for its residents. “Now you see people just walking around outside in random residential areas that they would never walk in, because there’s nothing there,” Papageorgiou said. “There is an occupation of the public space that’s unrelated to any commercial activity. It’s just purely being out in the city.” He pushes his son’s stroller down the middle of the empty street. There’s a sense of reclamation as residents stay in their own neighborhoods, like newly sequestered villages. “You meet people outside, everyone says hi to each other. It’s very strange,” he said.

In most cities, the routine of social life was made up of exactly the kinds of businesses that had to close during the pandemic: restaurants, bars, hotels, and cafés. New development was happening in the commercial sector, Papageorgiou said. Now “the only space we can use is private space or public space; there is no intermediate.” Just as we’ve become aware of every minute flaw in our own homes, we’re also confronting the limits of public space. Streets are empty, but sidewalks can be crowded with people and must be approached defensively. Infrastructure like parks, pools, beaches, and playgrounds—all the facilities that make dense urban living bearable—are either shuttered or paranoia-inducing, the temptation to visit them balanced by the threat of exposure to the virus.

One of the most vital uses of public space—gathering in the streets, in protests, as people in every state across the country have done in recent weeks—comes with added risk and more scrutiny. Other mass actions have taken place in recent months, some at the peak of social distancing. Papageorgiou noted that during Greece’s Labor Day march in Athens, the demonstrators all kept two metres apart. “It was a little bit military-looking,” he said—“a grid of people dispersed into the public space.” On April 19th, more than two thousand protesters in Tel Aviv gathered in Rabin Square to demonstrate against anti-democratic measures passed by the government. Aerial photos show the same grid, protesters evenly dispersed with a perfection motivated by communal fear. In the U.S., the communal anger over the death of George Floyd and others killed by police seemed to overwhelm the concern for social distancing, but protesters were largely careful to wear masks, and a bump in cases linked to the demonstrations has not yet materialized. Still, the pandemic makes it easier for critics to discount protests by arguing that they are dangerous or excessive, even as restaurants begin opening up again. The public realm has become fraught, to an extreme.

So far, the pandemic’s impact on urbanism has shown up in small changes that can be implemented faster than a new building or zoning plan. Lithuania’s capital, Vilnius, opened closed streets to restaurants and cafés so that tables could be set up at appropriate distances. New York City has made forty miles of streets pedestrian-only to expand access to the outdoors away from parks. London is laying out a vast network of new bike lanes. Tobias Armborst, a principal of the Brooklyn and Detroit architecture-and-urban-planning firm Interboro, said that these interventions fell under the label of “tactical urbanism”: “Urbanism that is not master-planned but comes from the bottom up.” Tactical urbanism had been the province of guerrilla gardens and flash mobs, but city groups like New York’s Department of Transportation have gradually adopted the strategy of iterative, small-scale experiments.

The pedestrian streets were “overdue,” Armborst said, a counter to the dominance of cars. “It’s a ridiculous situation that so much of urban space is given up to the stupid boxes standing around most of the time.” Georgeen Theodore, another Interboro principal, said that the upheaval makes it easier to imagine dramatic changes: “When you have a momentary lapsing of the status quo, it allows everyone to see that something’s possible.” During the quarantine, the firm has been working with institutional clients like universities to figure out how best to reopen. They’re evaluating the strategy of holding classes outside, a model that might be extended to public museums or libraries. Interior functions are expanding into exterior landscapes.

The future of cities will be a fundamental question of density. In the eighteen-fifties, Georges-Eugène Haussmann began his remaking of Paris, demolishing crowded medieval neighborhoods, which were thought of as pestilential, in favor of broad avenues and grand city plans with geometric parks and public squares—the precursor to Euclidean modernist developments in the twentieth century. Over the past few decades, urbanism focussed on undoing this model, cultivating organic density through affordable housing, ever-smaller capsule studio apartments, and mixed-use zoning. Now, once again, as a response to disease, Armborst said, “we’re in a situation where density is something to be avoided.” The challenge is reconciling the need for a long-term architectural plan with the pandemic’s ongoing unknowability.

In a brief pandemic-era manifesto that he circulated among colleagues and friends, Holl wrote that architecture “should embrace our codependence.” Buildings can make us more aware of the ways in which we are globally connected—the pathways that spread the coronavirus but can also help us fight it, collectively. The earth’s health is inextricable from humanity’s; connections between the two can be cultivated in the design of a large-scale apartment building—like Holl’s Linked Hybrid, in Beijing, which interweaves public and private space—just as much as in that of a cabin.

A similar attentiveness can be found on our own city blocks as we circle them for the umpteenth time. There is always more to notice in the specificity of a single place or space. “We’ll appreciate the local and the regional in a different way first,” Deborah Berke said. “That will positively influence the global experience when we get back out there again.”