The world's longest known cave system.

This too-low North Carolina railroad trestle is still a notorious big rig executioner.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

Meet manatees face-to-face at this zoo for native species.

A building so large that it has its own weather.

Ruins of a Carnegie family mansion on Cumberland Island.

A tribute to Ponce de Leon's supposed quest for eternal youth.

This "Palace of Purification" has made many film appearances as a dark and sinister headquarters.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.

A geological mystery on Camelback Mountain.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

When ecosystems collide in the arid Southwest.

A bizarre roadside attraction and the first instance of miniature golf in the world.

At 207 feet, one of the world's longest continuous escalators.

A historic coal mine that doubles as a museum and tourist attraction.

A 120-year-old legend concerning an empty circular patch in the North Carolina woods.

A bizarre house filled with an astounding array of collections.

Gargantuan home of Russian science.

Former headquarters of the KGB.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

World's largest bell sits on the grounds of the Kremlin in Moscow.