The hallucinogenic center of the ancient world.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

These small, triangular, colorful houses are a staple of Madeira Island.

Exploring the wilder, more passionate sibling of Erg Chebbi feels like discovering a secret sun-kissed planet from another galaxy.

God's Saharan sandbox of wrath.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

Traditional 11th-century outdoor tannery.

A Moroccan getaway in the mountain range that plays the Himalayas' stunt double.

The remains of a magnificent medieval fortress that was the capital of a vast empire.

The deserted pirate-themed restaurant still entices explorers.

Historic medieval fortified city in southwest France.

There is a strange little carving of a person seemingly crushed by a pillar behind the remains of St. Thomas Aquinas.

A dark, narrow tunnel that leads to a charming lake and waterfall.

This former community granary is now a lonely mountaintop shrine.

This Art Nouveau gate still stands at the former entrance of a 20th-century Spanish writer's colony.

An automaton perched above an classic clock and watch store

A subterranean relic of the Spanish Civil War hides below this picturesque park.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

An abandoned horror film set sits eerily along a highway through Hollywood's "door to the desert."

This unique structure allowed boats to bypass underwater mine barriers in the channel to enter the harbor.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.