In Spain, the ruins of a Roman military camp sit along a flooded section of a river.

38-story baroque tower reflecting Detroit's rise, fall, and possible rise again.

To truly appreciate Detroit's landmark skyscraper, you have to step inside.

This sprawling bookstore spans four floors and has more than a million books in stock.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

A monument to the egos of two railroad magnates that fell into decline along with their careers.

Built in 1981 in collaboration with Andy Warhol, this giant piece of pop art stands on the campus of Colorado State University.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

This chapel is the site of a yearly pilgrimage that originated during the Middle Ages.

A submerged village appears when dam levels drop.

These narrow stone granaries have been used to store and dry out grain for hundreds of years.

A cluster of granite granaries perched on stilts.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

A natural formation that resembles a camel resting in the New Mexico desert.

The largest island on the great salt lake is home to curious creatures and strange stories.

The largest wildlife crossing in Utah allows local fauna to safely traverse the six-lane Interstate 80 at Parleys Canyon.

On the edge of grassland in northeastern Colorado, these rock formations are some of the few remnants of a high plain that has eroded away over millions of years.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

More than 21,000 images fill this overlooked gem of a prehistoric site.

The remains of a historic ranch house that witnessed the Civil War battle dubbed the “Gettysburg of the West.”

Despite time, colonization, and the brutal New Mexican heat, these Pueblo ruins still stand.

This giant pocket watch is the third iteration of a local landmark that has been standing just off the Santa Fe Plaza for over 100 years.

The oldest continuously occupied public building in the United States.

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.