New York's subways are renowned for their freedom—freedom to eat, sleep, and furiously lick shoes. But our subterranean limousine lacks reliable facilities. Where can one evacuate with dignity? You can't pull a "2 Train Trapeze" without some scold noticing, and exiting means saving your kidneys at the expense of your bank account. Human washroom dowsing rod Eron Watt has pinpointed all 129 restrooms in the subway system, but only 48 are open for use. What gives?

Some subway restrooms have been converted to newsstands (Astor Place), others have been changed to storage rooms or workstations for MTA employees. Watt's initial 2012 offering, NYC Subway Public Restrooms: 45 Places, is the Citizen Kane of shakily shot subway restroom tutorials. Of the 43-minute film, Leonard Maltin said, "There is no way I'd take a crap in most of those places but I'd probably pee in them, yeah, sure, just please stop calling me."

Earlier this month, Watt debuted NYC Subway Public Restrooms: 3 More Places, which revealed new usable restrooms at the Forest Hills E/F/M/R station, the Court Street R / 2/3/4/5 Borough Hall stop, and the 62nd Street D / New Utrecht Ave N stop. "Simply dazzling," raved A.O. Scott, "Now leave my hotel room or I'm calling the police."

According to Untapped Cities, many subway restrooms are locked. But MTA spokesman Adam Lisberg (actually) told us that except for when they are under construction, the only times bathrooms are locked is from 1 a.m. to 6 a.m. for cleaning purposes or to prevent the potential for crime. An official bathroom count wasn't immediately available, but since some of Watt's knowledge is a few years old, the porcelain landscape may have changed.

For more essential bathroom knowledge, here's a "Secret List" of public bathrooms from Reddit.