2. Hidden Concourse at 1271 6th Avenue
This obscure tunnel is hidden in plain sight and open to the public. Anyone who has gotten off the subway at 47-50 St-Rockefeller Center is familiar with the large concourse that surrounds the subway station, offering access to various stores and the basement of Rockefeller Center, where one can buy tickets for Top of the Rock.
A far lesser known portion of this concourse can be found hidden behind a door that simply looks like it leads into another generic office building. At the far northwest corner of the subway concourse, you will find a set of revolving doors labeled “1271 6th Avenue.” Entering these doors is actually like entering a whole other subterranean world. You are greeted by the cleanest, brightest underground space in midtown. A long hallway ducks into building basements and works all the way up to 1285 6th Avenue between 51st and 52nd streets, and as far west as the breezeway behind 777 7th avenue.