These precariously placed ruins harken back to a 13th-century castle.

Although resembling a grand Buddhist temple, this structure is actually the largest mosque in China.

One of Vietnam's most iconic landmarks was built by Japanese traders and is now in danger of sinking.

A domino effect created with Britain’s iconic telephone boxes.

Nelson Mandela lived here with his family from 1946 until his arrest in 1962.

This memorial complex contains several mass graves for victims of the Siege of Leningrad.

The largest caravanserai in Cyprus also includes amazing examples of Ottoman architecture.

Gothic tower where Lord Alfred Tennyson wrote the poem "The Sleeping Beauty."

These small, triangular, colorful houses are a staple of Madeira Island.

This glass skywalk offers vertiginous views down the volcanic cliffs to the beach below.

Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

A lush oasis full of vibrant plants and striking geometric displays.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

A grand example of 19th century Burmese teak architecture, and the most significant of Mandalay's historic buildings.

One of the earliest depictions of an Arthurian scene that is shrouded in mystery.

This Renaissance palace features a unique architectural design and is now home to the Ferrara National Art Gallery.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

The last king of Poland was interred in this church nearly 200 years after his death.

Three columns of volcanic rock shoot out of the ocean.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

The hallucinogenic center of the ancient world.

The castle still holds traces of the abandoned Roman fort it was built atop.

Chelsea's soldiers were given strict orders when crossing this historic bridge.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.