A vast Communist-era exhibition space in the Bulgarian capital.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

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

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

A hidden three-foot-wide house separates these two regal churches.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

The stunning interior of this Gothic church is covered in ornate gold details.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

Mosaics, storks, and brothels—this ancient city has it all.

The ruins of an early-18th-century complex that could once house up to 12,000 horses.

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

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

Traditional 11th-century outdoor tannery.

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

One of the most spectacular canyons in the world.

This vast masterpiece of Moroccan architecture spreads across 20 acres.

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

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

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

Once home to one of the oldest banks in the world, this building is also where Marco Polo's famous travelogue was written.

This cathedral hides a sculpted dog that determines your fate and an unexploded shell from World War II.

This amazing medieval fortress stands atop a promontory along the famous Cinque Terre.

The bomb-ravaged remains of of a colossal Neptune.