The Atlantic Avenue Tunnel

Under Atlantic Avenue in Brooklyn runs the oldest subway tunnel in the world, built in 1844 for the Long Island Rail Road, sealed and forgotten in 1861, and rediscovered in 1980 by a young man named Bob Diamond who crawled in through a manhole in the street. Half a mile of stone-arched tunnel still lies down there in the dark. Public tours ran for years before a safety dispute closed them; the tunnel and its rediscovery are documented history.