The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

Venue for strange sideshow displays and musical acts.

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

One man's homage to the sun continues to grow like a glass fractal.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

The United States Capitol's former columns still stand.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

America's most famous piece of self-built architecture.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Elevated freight railway turned wildly successful urban park.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

An enormous, inside-out glass globe built in 1935.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A 140-year-old castle with underground caves hidden in San Francisco.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.