Tunnel Number 3

The State of New York began digging Water Tunnel No. 3, the largest capital construction project in New York City history, in 1970 to provide water to the city from its upstate source. Portions of the tunnel were placed into service in 1998 and 2013 and the remaining sections are expected to be complete by 2032.

Upon completion, the tunnel will be over 60 miles (97 km) long and travel 500 feet (150 m) below street level in sections -- snaking across the city from Yonkers underneath Central Park, the East River, and Roosevelt Island before finally ending up in Astoria, Queens.

The ambitious construction project has cost over $6 billion and its high costs go beyond dollars with 23 workers losing their lives to the tunnel, an average of about one life each mile.