Virgil's many-mouthed gateway to the underworld.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

A deadly ancient portal to the underworld.

Stunning wetlands ablaze with pink lotus flowers.

An underwater city for the dead.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.

This attraction was abandoned after the Chernobyl disaster.

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

On stormy days debris from this unfinished and abandoned skyscraper rains down on the Bangkok streets.

Most polluted lake in the world, used as a radioactive dumping ground for years.

An enormous, 30-story-deep hole in the middle of Guatemala City.

An amusement park on the grounds of an unused nuclear power plant, with a swing ride inside the cooling tower.

Abandoned silver mine strewn with wrecked and twisted structures.

The largest stone moai on Rapa Nui.

Peace Park and the Atomic Bomb Dome.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

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

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.

Mysterious craters may have been home to an ancient cult.

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.