Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

An abandoned mine now resembles a post-apocalyptic landscape of derelict buildings and blood-red pools of water.

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

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.

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.

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

An exquisite collection of fairytale conveyances that puts most car museums to shame.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

The world's oldest bookshop still in operation.

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

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

Catering to broken dolls for almost 200 years, this repair shop is now a charnel house of doll parts.

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

A neolithic tomb converted into a tiny chapel.

This crumbling Portuguese ruin overlooks the populace it once ruled.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

Houses are tucked between, on, and underneath giant boulders.

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

Elaborate tile work in this railway station tells the story of Portugal.

Ancient catacombs form the foundation for this Rococo orgy of a church.

The corpse bride of Portugal.

The medieval castle built as headquarters for the Pope's secretive Knights Templar.