Submerged busts of communist and socialist figures from the USSR.

The world's smallest movie theater runs on solar power—an attraction in itself.

The royal seat of Henri Christophe, a formerly enslaved man who became Haiti's only king.

Park filled with machinery that drove the southern agriculture and oil industries forward.

Rare karst landscape eroded from a flat seabed.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

The first hospital in the New World.

This complex of vertically-excavated Buddhist, Jain, and Hindu monolithic temples in India's Maharashtra providence illustrates a spirit of tolerance characteristic of ancient India.

A nuclear power plant abandoned along with an international allegience.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

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

Fantastically decorated underground chambers built in the 1760s.

An abandoned saucer-shaped monument in the Bulgarian mountains.

Part of one of the largest flooded cavities on the planet, and littered with prehistoric animal bones.

The former Willingdon Airport started operations in 1929, in India's capital, Delhi. Now, it's used for maintenance runs and helicopter rides.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

A contemporary art installation housed within a Gothic cathedral.

The only surviving prototype for Buckminster Fuller's house of the future.

The final stronghold of a king whose feet never touched the ground.

At the "Garage Mahal" in Houston, car culture is about more than just driving.

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

A memorial to the murdered Jews of Kaunas.

Landscape of bizarrely shaped desert mountains and innumerable rock carvings.

A perfect turquoise lake colored with glacier dust.