Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

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

This former royal palace with gorgeous gardens became the first museum in Morocco.

The oldest known university in the world is in Fez, Morocco.

Traditional 11th-century outdoor tannery.

Crumbling necropolis set high above Fez.

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

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

The other side is actually green.

Over the dunes of the Empty Quarter, the mysterious music of the desert.

An ancient fortified mound raised over the millennia from settlements built one on top of the other.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

Former headquarters of the KGB.

Some Moscow residents once claimed the bizarre, contorted mass of metal on top of the building was used to manipulate minds.

A former special storage facility for documents during the Cold War.

A sculpture park of the tossed aside relics of the USSR, from Stalin to a massive Soviet emblem.

This massive monument honors the first human in space.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

This triumphal arch is the only fully standing structure that remains from Roman-era Oea.

Magnificent Roman ruins lie vulnerable to destruction on the edge of the Mediterranean.