Once America's longest-manned military fort, now an abandoned hulk.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

Over 1.3 million confiscated wildlife products fill this macabre menagerie of illegal animal specimens.