A winding, cliffside stretch of road overlooking the Delaware River.

Discovered by cows, these upstate New York show caves are presented with a healthy dose of psychedelic folk art.

Holding the most bodies of any cemetery in the United States.

Rummage through this sunken ship, but leave your scuba gear at home.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

Avoid gangster interaction while window-shopping.

Lie in a hammock where George Washington stood.

A bit of retro transportation flair preserved in the world's largest department store.

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

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

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

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

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

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A pride of the state, this working museum crafts pottery mosaics in the style of Pennsylvania's earliest European settlers.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

A local landmark with generations of spraypainted messages, and more being added each day.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

St. Augustine's record-setting narrow street was designed to protect against pirates.