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

An underground city of salt.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

A surreal statue honoring Prague's favorite literary son.

This automated sculpture of two men peeing will spell out text messages with their micturition.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

Neo-cave art on the macro scale.

Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The tallest hotel in Europe.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

A battle between nature and architecture in the Cambodian jungle.

Artifacts and memories from the Vietnam war, located in a place that experienced it first hand.

A desert in southeast Asia, complete with a beautiful lake covered in lotus flowers.

The lavish temple of the Cao Dai religion that includes Buddha, Mohammed, Joan of Arc, and Victor Hugo.

These crumbling towers are some of the last remnants of a centuries-old Vietnamese culture.