When the rain falls, this drain system turns into a musical instrument.

A natural arch offers panoramic views of Yangshuo's karst hills.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

Ice roads, deep holes and 3,500 pounds of diamonds.

The world's second-largest excavated hole.

A 4th-century Roman church complete with a hidden underground cave.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

This gravesite in the Amazon Rainforest was left behind by a failed Third Reich expedition.

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

This boulder stays on its mountain thanks to a huge chain and on the map due to local legend.

These barriers stand as stark reminders of Northern Ireland's troubled past.

The pit stop from "The Texas Chainsaw Massacre" now serves beef and pork barbecue, not people.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

Surreal riveted sea forts once protected the Kent shores from German attack.

An abandoned horticulture institute gloomily presides over rows of derelict and vine-wrought greenhouses.

These abandoned Cold War-era bunkers are now a designated refuge for endangered bat species.

This imposing 20th-century castle was abandoned before it was ever completed.

An abandoned Jewish sanatorium is tucked within the woods of Poland.

The ruins of an abandoned church loom within a picturesque Ukranian village.

One of the most poignant ruins of the Chernobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.

This attraction was abandoned after the Chernobyl disaster.

This is what trains will look like after the zombie apocalypse.