The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

This large midwestern cavern features impressive rock formations and an underground waterfall.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

These huge stone ovens in the desert fueled the Nevada silver boom, and may have also been a hideout for outlaws.

This golf ball–shaped former desert real estate office now houses a UFO museum.

A Saint Nicholas-themed ghost town in the Mojave desert.

Henry Ford's failed rubber plantation in the middle of the Amazon rain forest.

Ancient rock-hewn town that witnessed key events of Georgian history.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Death rituals and sacrifice inside a Peruvian megalith.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

This abandoned fort is said to be the most haunted place in India, so much so that entry is prohibited after sunset.

The ruins on a deserted tropical island in the Philippines bear the scars of WWII.

A tiny island home to a former English slave fort.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

An abandoned stretch of highway, deteriorating next to the operational one.

Plagued by riots, celebrity injuries and a tragic death, this amusement park has been demolished.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

One man's artistic vision is a small town government's legal battle.

Tribute to the Chinese people of Young and Australia.

Final resting place for hundreds of prisoners of war.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.