This irregularly shaped sea fortress has defended not one but three different sovereign states.

This endearingly discomfited urinating statue commemorates the sneaky pees had by us all.

A subterranean house of worship carved right out of the bedrock.

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

Elaborate tile work in this railway station tells the story of Portugal.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

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

Come for the flowers, stay for the bats!

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

A battle between nature and architecture in the Cambodian jungle.

Khmer Rouge's high security prison.

5,000 skulls in memorial to those killed by the Khmer Rouge.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Tiny memorials honor individual victims of the Holocaust.

Cold war icon and onetime "hole" in the iron curtain.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

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

The most visited, and possibly most controversial, museum in Germany.

An Inca spa, military outpost or maybe… both?

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

A Christian monastery stands on what was once a holy Incan temple.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.