Yesterday's water main break at West 106th Street and Central Park West flooded neighboring streets—and subways—and left a huge sinkhole. And it was pretty startling when the main broke after 11 a.m.—a witness named "Cowboy" told WPIX it was a "boom! It was an explosion, definitely." A more conventionally-named witness, Elizabeth, added, "It sort of looks like California looks after an earthquake."

The Department of Environmental Protection says the 30" cast-iron pipe was made in 1917. DEP Commissioner Carter Strickland told DNAinfo "that several factors can contribute to a water main breaking, not just the age of the pipe. Extreme weather, freezing temperatures and construction all affect water mains. He said that the only way that officials will learn what caused Monday's break is to excavate the broken pipe and examine it."

A DEP spokesman also said, "It's not dangerous. It's not a public health risk," but it was certainly annoying for residents, whose buildings were flooded, and commuters, whose evening commutes turned into bit parts in a Day After Tomorrow sequel.

For a crumbling infrastructure flashback, in 2007, a 24" steam pipe installed in 1924 exploded near Grand Central, causing numerous injuries.