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

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

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

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

Perhaps the most spectacular grotto along the Algarve coastline.

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

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

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

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

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

The world's oldest bookshop still in operation.

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

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

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

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

Go inside to really appreciate this 500-year-old technological masterpiece.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

2300-year-old Roman road connecting the empire.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

Walk through a fairytale in Tuscany.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

You've probably seen these distinctive orange-tiled columns on the big screen.

Berlin's old airport.