The largest dinosaur trackway in North America is tucked away among this canyon's ghosts and archaeological gems.

Tracks near this Texas nature site were once thought to support the Creationist belief that man and dino coexisted.

The ancient past meets the retro-future at these dinosaur tracks that are protected by a geodesic dome.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

Symbolic attempt to overcome the issues of life.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

Once adorning a New York skyscraper, these reclaimed ruins now haunt an Indiana park.

A medical facility that has been kept frozen in time.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

A hillbilly theme park that proved so unpopular the land wouldn't even sell on eBay after it closed.

A unique attraction and museum dedicated to exploring iconic roadside structures.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

Less a museum than a bizarre fantasy world created by artists and engineers.

Legends surround this jagged rock formation in the New Mexico desert.

A dreamy mausoleum honors Persia's most famous poet.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

The Victorian-era greenhouse is stuffed with tropical plants, and open 365 days a year.

A once-luxurious, now abandoned hotel in the Italian Alps.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

With nearly double the depth of the Grand Canyon, this Peruvian canyon is one of the deepest in the world.