Vibrant street art created with mixed media.

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

This house's itty bitty size means no humans allowed.

This eatery re-creates dishes from the Ottoman Empire so you can dine like a sultan.

Turkish adventurer antiques in the heart of the Grand Bazaar.

A marvel of Byzantine engineering under the streets of Istanbul.

Housed in an old British jail, this spot serves up Georgian, Russian, and Ukrainian specialities with a side of Turkish history.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

A flooded Mexican cave that hides a river beneath the water.

Medicinal spa created with the discharge from a geothermal energy plant.

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This extremely remote border crossing was closed to prevent smuggling and looting.

People have been scribbling on this massive chunk of granite for more than 1,500 years.

A beloved tribute to the Fab Four and the freedoms they inspired.

An exceptional assortment of fossils recovered from private collections.

Dinosaur eggs were first discovered at these fiery red cliffs.

A jagged silhouette of shamanistic stone heaps rises from the shore of this dazzling mile-high lake.

Mongolian Buddhists believe this monastery in the Gobi desert to be the center of the world's spiritual energy.

This spiritual landmark for practicers of Shamanism is drenched in milk and vodka and covered in blue scarves.

Just in case you need some cold cash at the top of the world.

A place as enchanting as the journey to reach it is harrowing.