Scientists have confirmed what many New Yorkers have long known to be true: The city’s 24-hour subway system is crawling with microscopic life. The trains that transport nearly 5.5 million human riders a day are also home to over 15,000 types of bacteria, including such unpleasant pathogens as the bubonic plague and streptococcus, a bacterium in the same group as those that cause threat infections and pneumonia. What scientists found most shocking, however, was that over 48 percent of all the samples identified were a total mystery, according to study released Thursday by researchers at Weill Cornell Medical College in Manhattan.

“Half of our high-quality sequence reads do not match any known organism, which … demonstrates the large, unknown catalog of life directly beneath our fingertips that remains to be discovered and characterized,” the study authors noted in their report. “Because the majority of the DNA left on surfaces is bacterial, many of these unknown DNA fragments likely represent un-culturable species and strains of bacteria.”

The project was called PathoMap and took 17 months to put together. Researchers swabbed turnstiles, railings, ticket kiosks and benches at subway stations all over the city. Some of what they found was expected – traces of rats, mice, lice, beetles, flies and flees. Other discoveries were not. Researchers documented bacteria linked to diseases like the bubonic plague and staph infections, as well as those associated with food poisoning, heart-valve infections and even anthrax, although not enough to pose any danger.

“People don’t look at a subway pole and think, ‘It’s teeming with life,’” Christopher E. Mason, a geneticist at Weill Cornell Medical College and the lead author of the study, told the New York Times. “After this study, they may. But I want them to think of it the same way you’d look at a rain forest, and be almost in awe and wonder -- effectively, that there are all these species present, and that you’ve been healthy all along.”

Researchers also identified microscopic samples of everyday, innocuous substances like sunscreen and mozzarella cheese. To search the map by station, click here. Red areas represent the locations with the highest bacteria populations. Cooler colors show areas with less germ activity.