The largest pool at its elevation sits on top of one of the most expensive resorts in the world.

Where the Great Wall of China meets the sea.

Nazca pilgrimage site covering 370 acres is a popular stop for archeologists and looters.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

The only castle in North America to ever house European sovereigns.

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

The first "Hall of Fame" in America was designed by legendary Gilded Age architect Stanford White for what was then the NYU uptown campus.

A building so large that it has its own weather.

Phil Mortillaro uses keys to bring art back to the Village.

This jail which was in service for over a century is now open for curious visitors.

This abandoned sea fort has become an accidental bird sanctuary.

This museum offers an actual time machine back through Colorado's past.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

The labyrinthine storm tunnels beneath the city of Melbourne are ruled by a band of urban explorers.

This famous city eluded concrete detection until the early 2000's.

The world's first commercial spaceport is a disappointment of cosmic proportions.

This North Carolina store preserves a historic moment in America's movement for racial equality.

The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.

Huge concrete structures designed as an early warning system for Britain to detect enemy aircraft.

Bridge that died in war and was resurected.

A whimsical bridge adorned with decorative dragons.