New York Times:

Researchers at Weill Cornell Medical College released a study on Thursday that mapped DNA found in New York’s subway system — a crowded, largely subterranean behemoth that carries 5.5 million riders on an average weekday, and is filled with hundreds of species of bacteria (mostly harmless), the occasional spot of bubonic plague, and a universe of enigmas. Almost half of the DNA found on the system’s surfaces did not match any known organism and just 0.2 percent matched the human genome.

I’m never taking the New York City subway ever again.