An annual two-week festival near the city of Riyadh when Saudis let their hair down.

This giant volcanic crater holds its very own field of salt.

Site where Moses may have received the Ten Commandments.

An archaeological site believed to be the burial place of the "mother of us all."

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

Within the Saudi Arabian desert lies a 2,000-year-old ghost town made of stone and mud.

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

An unfinished tomb carved into a giant boulder in the Arabian Desert.

No one knows who's responsible for decorating this tunnel with stuffed animals, but the people love it enough to protest their removal.

This Stockholm light tower can be controlled by anyone with a smartphone.

The library's graceful rotunda is like a bibliophile's temple.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.