At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

Dedicated to the European Sinti and Roma peoples murdered during the Holocaust.

A monument to the man who almost killed Hitler.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

This strange sculpture depicts a giant nightmare hare crushing a man to death beneath its colossal bulk.

Dine like an American revolutionary at Colonial Williamsburg.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The discovery of these rare, ancient artifacts led to the creation of a new museum.

The world's most elegant power lines.

Single runway interrupted by a busy road that cuts across its middle.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

An early 20th-century bullring converted into a modern shopping center.

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

This statue of the great Argentinian car driver is located near a famous curve of the Monaco Grand Prix.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

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

A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

Legend says this sacred tree was a gift from goddess Athena.