The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

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

The newsstand that never closes its doors—well, almost never.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

A nuclear power plant abandoned along with an international allegience.

An eatery for UFO seekers on the Extraterrestrial Highway.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Cathedral carved out of salt, located a mile below the earth's surface.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This nearly endless university hallway is home to a unique sunset known as "MIThenge."

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

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

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

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

Crumbling necropolis set high above Fez.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Guatemalan womanizer, venerated during Holy Week.

A massive underwater sinkhole made famous by Jacques Cousteau.

Hot springs monkey spa in the middle of Hell's Valley.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

Europe’s oldest natural human mummy.

A "miracle" that seems to produce more holy fistfights than holy revelations.

Modern museum, designed for Jihadi tourists.