One of the smallest bookstores on the planet.

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

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This charming candle shop has been in business since 1789.

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

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

The world's oldest bookshop still in operation.

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

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

A fairy tale castle in modern Rome.

Jesus' footprints and the first catacombs in the world.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

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

Rome's semi-secret peephole vista is also a former Crusader stronghold.

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

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

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

A hands-on traveling collection of the innovative devices of yesteryear.

A tribute to the incredible generosity the Choctaw Nation showed the Irish people during the Great Famine.

A Milanese café entirely designed by the American director Wes Anderson.

This giant wooden treehouse within a sprawling garden has its own eatery.