so a few weeks ago i went on the atlantic ave. subway tour in brooklyn, which, you can sign up for on this website. the tunnel was built in 1844 and was apparently lost for a great number of years before being rediscovered by the fellow who runs the tours. it's currently $15 but well worth the experience.
my shitty little digital camera couldn't get any real clear shots of the inside of the tunnel so here i present to you a picture of the manhole cover we had to go through, followed by DARKNESS!
pictures by people with better cameras can be found here