As you may have heard, New York City has been planning to add a subway line beneath Second Avenue since the days of the Great Depression. Work finally started a few years ago and the tunnels are scheduled to be completed in 2016.

A massive undertaking in terms of engineering, the tunnel has managed to stay out of the news and most New Yorkers go about their days oblivious to just what is going on deep within the bedrock beneath the Big Apple.

It addition to visits from Catholic priests to bless the tunnels, the man-made caverns are the domain of the "sandhogs," who use heavy machinery and plain old sledgehammers to blast their way through the rock.

For the curious, last week's New York Times Magazine offered a mind-blowing peek into these tunnels, revealing just how much human effort and ingenuity is required for something as mundane as a simple trip uptown on the subway.