An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

These Nubian pyramids are strange and unique, even by pyramid standards.

Remains of an abandoned coral city.

Village of slate houses, built on a white marble outcrop.

One of the most remote and isolated villages on the Arabian Peninsula.

A city built from mud and known as the "Manhattan of the desert."

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

The palace of the King of Kings, burned by Alexander the Great.

Putrefaction plateaus in Iran, where the dead were sent for decontamination before going to their final resting place.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

Mausoleum and Holy Seat of Antiochus I of Commagene.

A 1,500-year-old ghost settlement is slowly fading away.

What is left of the pillar of Saint Simeon, the voluntary martyr who climbed the column to give his sermons, remaining perched there for thirty-seven years.

A Turkish monastery tucked into a cliff wall.

The hermits of Karoulia protect their asocial lifestyles by living on the vertical face of a treacherous precipice.

This famous city eluded concrete detection until the early 2000's.

A battle between nature and architecture in the Cambodian jungle.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

More than 100 monumental tombs carved into rock are preserved at this ancient Nabataean site in the Arabian Desert.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

The central mosque of this Mali town is entirely built from mud.

Cliffside houses provide a spectacular view from their perch above the valley.

Naturally protected city carved from a rock face.

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