A patchwork of ruins from various civilizations in one of the world's oldest continually inhabited cities.

A monumental underground karstic wonderland is also the water source for over a million citizens of Beirut.

The largest hewn stone in history.

A space dedicated to contemporary art and culture, co-chaired by fashion icon Miuccia Prada.

A marvel of Byzantine engineering under the streets of Istanbul.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

The celebrated eyesore created by starry-eyed sweethearts.

Festival of Perpetual Life and Rebirth.

Foreign invaders almost left this lovely Caucasus palace alone—almost.

A shrine of fire worship built on top of a natural flame.

A quirky house created entirely out of glass bottles combines a collector's spirit with an artist's flair.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

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

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

A unique seaside cave where Aleister Crowley faked his own death.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

Southern Italy's spinning top village.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The notorious "Hanoi Hilton" where Vietnamese colonial subjects and later American POWs, including John McCain, were imprisoned.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.