Go underground with New York's 'Sandhogs,' the unseen workers who dig the city's tunnels

If you live in New York City and took the subway recently, or used one of the underwater highway tunnels, or even turned on a faucet, you have a group of men (and a few women) to thank. Since 1872, Union 147 -- or the Sandhogs, as they're popularly known -- has worked underground to excavate and construct most subterranean infrastructure projects for the city, clearing and blasting million-year old bedrock and creating tunnels for various uses. Beginning with the foundations for the Brooklyn Bri...