Silver in the hills led to the speedy creation of this boom town and a lack of it saw the town abandoned nearly as quickly.

This sawtooth mountain range still bears the strangely lovely marks of its history as a medieval quarry.

The largest Neolithic ruins in the world hide a notably clean prehistoric metropolis.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

A once grand hotel is being retaken by the wilderness it once capitalized on.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

Adobe ruins punctuate the beauty of an 800 foot canyon carved by the Canadian River.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

One of the largest caverns in the world has a maw large enough to stack cathedrals in.

The ruins of this abandoned fort now stand as a picturesque reminder of America's march West.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Ancient human, animal, and geometric figures drawn in the earth.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Enchanting cave with a river crashing through the roof.

Dolphins, ancient clams and hundreds of waterfalls make this one of the world's top tourist destinations.

This strange geological landscape erupts with sudden bursts of water.

The Dalai Lama named this New Zealand landscape the "Spiritual Center of the Universe."

Tubing through a cave lit with glowworms is a magical underground experience.

An extraordinary "City of Caves" carved from solid stone.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

This ancient subterranean megalopolis is known for the hot oil traps that were installed above each of its entrances.

This nearly abandoned plantation was once witness to an eclipse that proved Einstein's theory of relativity.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.