The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

The highest peak in Utah is the hardest to reach, but only if explorers choose the hard way.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A house carved into a rock in the 1940s.

Mind-blowing carvings and fantasy ice scenes grace the largest year-round ice environment in the world.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Travelers exchange letters with woodland creatures at this mini post office.

A motel dedicated to Southwestern nostalgia.

Dramatic river bend surrounds a natural red-rocked pedestal.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

The ruins of the castle that chemicals built.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.

World War II-era Nazi compound nestled in the Santa Monica hills.

"A hideous albatross in the Hudson River Valley."

The former home of France's controversial pop maestro is almost completely covered in ever-changing tributes and graffiti.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Most-visited and most-photographed slot canyon in the American Southwest.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Outsider Art Community.

Super-heavy Nazi architectural experiment.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.