The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

The compass on its front was a handy tool for 17th-century merchants who needed to know the direction of the wind.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

A fascinating and enormous collection of natural history exhibits stained by a dark colonial legacy.

This memorial museum chronicles the apocalyptic destruction of the First World War.

A moving memorial to the fallen and missing from WWI trenches.

Descend into the tunnels to experience the life of a coal miner.

A rare example of World War I trenches from the British front.

This abandoned Belgian fortress is purposefully being left to nature.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

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

Devoted Buddhists can earn enlightenment in the next life by crawling through this symbolic nostril.

The quintessential Japanese rock garden has existed for more than 500 years.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

God's Saharan sandbox of wrath.

A fortified city, home to a remaining population of five families

One of the most spectacular canyons in the world.

Since the 1700s, this old barrel has acted as a post box that relies on the kindness of travelers.

These mammoth-yet-narrow crevasses in the Earth are perfect for taking an otherworldly swim.

An old slave lookout in Cuba's historic sugar cane fields.

A focal point of the Cuban government, this city square features one of the most iconic images in the country.

Feed it cash, get your very own gold bar.