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

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

A war-torn Olympic relic is being overtaken by graffiti and nature.

Oriental bazaar in the heart of Sarajevo.

A monument on the pavement marks the spot where two cultures that shaped Sarajevo come together.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Bathe in these natural hot springs located high in the Andes Mountains.

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

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

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

A painting in the historic Cathedral Basilica depicts Jesus and his disciples dining on a traditional Peruvian menu.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

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

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

An immense cave that has served as an outlaw's treasure trove, an underground dance hall, a nuclear fallout shelter, and much more.

Austin’s nonprofit-run graffiti park where street art is meant to be painted over.