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

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

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

The ruins of an ancient Zoroastrian Tower of Silence believed to be the earliest example of the traditional funerary practice.

Giant cauldrons overflow with Uzbekistan's favorite rice dish at this cavernous dining hall.

Touching displays of wishes for peace from the Cold War era.

These "50 Fortresses" have been unearthed in the ancient oasis of Khwarezm.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Light still pours into the ruins of this ancient Islamic observatory.

Ancient barriers wrap around what was once an important stop along the Silk Road.

The Avenue of Mausolea is a series of grand palatial tombs.

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

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

A mud brick kasbah with a history of lavishness and traitorship.

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.

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

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

The other side is actually green.

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