The New York City subway is inundated with 13 million – 13 MILLION – gallons of water a day. Every day. Every dry day. If it’s raining, it’s full of even more water. And it turns out a big part of that is because our great forefathers before us had absolutely zero clue what they were doing.
Source: Gizmodo – How The Hubris Of Man Turned The New York City Subway Into Wet Trash