Incredible Journey: New York City Underground (article)

"What would you find if you could take a giant core sample of the Big Apple? A confusion of cables, gas and steam lines, a sliver of the subway, putrid sewers, and -- below it all -- huge water tunnels. Imagine venturing Under New York....New Yorkers go about unaware of what is happening just beneath their feet: Power pulses, information flies, and steam flows. The city’s infrastructure starts just below street level, but it doesn’t stop there." -- from the website. <http://www.nationalgeographic.com/