Ryan Socash of It’s History dives into the fascinating history of seemingly forgotten underground tunnels throughout New York City.

Surprisingly it’s not exactly difficult to lose track of a tunnel, and believe me, New York City has forgotten about several of their own. Be it from the city’s expansion, to the events of World War II or just plain old falling out of use the fact is there are cavernous mazes of man-made spaces under the city that have literally been lost and forgotten today.

This list includes the Cobble Hill Tunnel under Atlantic Avenue in Brooklyn, which had been closed due to concerns about spy activity several times over in the late 19th and early 20th centuries, was subsequently discovered by underground explorer Bob Diamond in 1981.

Socash also examines the lost mail tunnel between the Farley Post Office on Eighth Avenue and the Morgan Processing and Distribution Center on Ninth Avenue, the lost pool tunnels of McCarren Park in Williamsburg, Brooklyn, the historic tunnels under Columbia University, and the ever-mysterious Track 61 under the Waldorf Astoria Hotel that still has rumors swirling around it.

Many people believe that there is still a rail car remaining on track number 61 that belonged to president Franklin D Roosevelt…the only real connection that could be found between FDR and track number 61 was a Secret Service schedule during the campaign season of 1944 , where on October the 21st, he entered and exited the building using this railway sighting. Track 61 would end up concealing the comings and goings of several presidents throughout history and was prepared for use as recently as 2003 when it was laid out as an escape route for president George W Bush during a UN general Assembly meeting in the hotel.