You share more than a zip code with your neighbors. You also share bugs—microscopic organisms (think bacteria, fungi, and viruses). These microbial communities are called microbiomes, and they seem to have an impact on everything from digestion to allergies. They also happen to be everywhere—from your intestines to your phone's screen to the sidewalk beneath your feet.

But those bugs are tough to understand, because you can't see them. “There’s like this whole other invisible planet,” says Kevin Slavin, head of the Playful Systems group at the MIT Media Lab. In a new project called Holobiont Urbanism, Slavin's team is working to sample, sequence, and visualize the microbial makeup of New York City. Some of the team members are designers, engineers, and biologists.

Some of them are bees.

Bees typically forage no more than a mile and a half from their hives, but in their expeditions they come into contact with the microbes in their range, and those microbes stick. Slavin's group worked with apiarists to build beehives with removable trays at the bottom that collect detritus from the bees, like a crumb-catcher in a toaster. Then they put those hives all over Brooklyn and Queens (and Sydney, Melbourne, Venice, and Tokyo).

The team installed hives on roofs in Brooklyn, Queens, Sydney, Melbourne, Venice, and Tokyo, in order to gather microbial samples from the cities' neighborhoods. The bees venture 1.5 miles away from their hives, collecting various types of microbes along the way. The team of scientists and designers sequence that information and then create visualizations from the data that help people better understand their city's microbiome. The project on display at the Venice Biennale.

Researchers can gather up all those bee-crumbs and sequence the DNA they find. Subtract the bee genes and what's left represents the neighborhood microbiome. Slavin's team mapped all those genes into a a circular evolutionary tree—like a Hillis plot, but for specific urban areas. They also mapped microbes to their homes. New York City and Sydney, for example, both harbor the genera Polaromonas, Sphingopyxis, and Alicycliphilus, all of which feed on pollutants. But Venice has Meyerozyma guilliermondii and Penicillium chrysogenum, two dampness-loving fungi associated with wood rot.

What does that teach you about cities? Maybe not much. Cataloging bug DNA might not say much about the urban microbiome as a whole. "This is just using technology to create artistically valuable work," says Jack Gilbert, a microbiologist at Argonne National Laboratory who studies urban microbial ecosystems.

Holobiont Urbanism

That might be the point. “The goal in all of this is to produce an imagination around the microbiome,” Slavin says. The project's website says the work is trying to shift what the philosopher Michel Foucault called the "liminal horizon," which is some tough postmodern sledding but does get at the idea of looking at the world from a different perspective.

In other words, just being able to see this invisible microbial world is at least a step toward understanding it. “We don’t really know at this point what bacteria are on the walls of our home or the sidewalk or the subway,” says William Bonificio, co-founder of the American Microbiome Institute. A city is about more than architecture and infrastructure and people; it's about the bugs everyone shares, too.