Just outside of Jordan's capital lies an ancient castle and intriguing caves dating back to the Copper Age.

A more chill but no less fascinating version of the famous ancient archeological site.

One of the smallest bookstores on the planet.

This charming candle shop has been in business since 1789.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

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

Picturesque intersection of witchcraft and ancient Christianity.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

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

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

This small chapel is built of human bones and decorated with a golden skeleton.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The cave holds a spectacular array of stalactites and stalagmites, including one shaped like a giant human heart.

The decaying remains of a once-luxurious Soviet spa town.

A Frankenstein blend of science and art allows one tree to produce 40 different types of stone fruit.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

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