63rd Street Tunnel

The 63rd Street Tunnel is defined by a unique construction method that literally involved building parts of New York City in Maryland. Engineers prefabricated four massive concrete tube sections in Port Deposit, Maryland, then towed these giant structures up the Atlantic coast and through the harbor. Once they reached the East River, crews lowered the segments into pre-dug trenches on the riverbed, sinking them into place like pieces of a gargantuan puzzle. This immersed tube technique allowed the tunnel to take shape on the surface before ever touching the river floor.