The crumbling remains of a gold mine that was operational in the 1930s.

A glorious pub known for a spiteful printing feud and its famous typeface lost—then found—at the bottom of the Thames.

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

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

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

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

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

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

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

The world's oldest bookshop still in operation.

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

One of the smallest bookstores on the planet.

A huge Megalithic chamber tomb located behind a cafe.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

Guests can stay at a hotel in the former French abbey where lie the tombs of King Henry II and King Richard the Lionheart.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

Giant topiary dog once played a role in a terrorist bomb plot.

This huge abandoned fortress hidden inside a mountain holds a world of subterranean secrets.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

The evocative ruins of a medieval village.

Ancient paintings known as the "Sistine Chapel of Cave Art."

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

The largest underground church in Europe.

This medieval chapel is now a shrine to the region's favorite sport.