Long tunnels run under the ancient chariot racing circuit to the tower.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

The ruins of an ancient stadium that hosted gripping chariot and horse races.

A five-square-mile slice of Spain on the Mediterranean coast of North Africa.

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

An eerie collection of the surviving structures from a past celebration of the future.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

The world's largest wooden structure.

The final resting place of the great navigator, or maybe his brother.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

In this desolate valley resides a gorgeous set of rocks sporting a technicolor design.

The designated Jewish quarter in Fez dates back to the 15th century.

Morocco’s modern capital was once a haven for Barbary pirates, who went so far as to establish a republic of their own.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

A fortified city, home to a remaining population of five families

This ancient altar emerges from the thick forests to reveal the mysteries of Etruscan sacrificial rituals.

This amazingly preserved Doric temple was abandoned before it was ever completed.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

A horse statue that receives constant makeovers from graffiti artists and locals.

The great Danube river starts here.