World's first "penitentiary," meant to be humane, drove men insane.

Cave where bat-eating snakes hang down from the ceiling.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

Every equinox this Maya pyramid puts on a spooky ancient light show.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

This restored 17th century synagogue is one of the few remaining structures in Morocco’s ruined Jewish quarters.

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

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

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

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

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

Traditional 11th-century outdoor tannery.

God's Saharan sandbox of wrath.

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

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.

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

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

The other side is actually green.

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

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

One of the most spectacular canyons in the world.

Founded as a refugee camp, now a popular tourist spot.