The Greatest Tunnel Ever Built(2008)

"Sandhogs" are New York's urban miners who for 150 years have carved tunnels into the city's bedrock, making life possible for the millions above. For the last 40 years, they've been working on their biggest job ever. The future of NYC, if not the nation, is literally in their hands. Are they up to the task? Will they finish in time? Narrated by Edward Burns, this award winning documentary goes deep into NY's underground to find out.