This (occupied) house is 10 feet wide and full of spite.

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.

These giant metal horses graze on a hilltop near the Montana highway.

The only road through the heart of Glacier National Park.

This amazingly preserved Gold Rush town is a historian's dream.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

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

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

A former gold rush boomtown has managed to stay in business for over 100 ramshackle years.

Rare and gorgeous birds abound in this protected wildlife sanctuary.

Home to the deepest rift anywhere on Earth.

Supposedly Satanic numbers adorn this preserved submarine sail.

A 6-mile-long lake created by an apocalyptic seismic event and the deadly chain reaction that ensued.

This record-setting hydraulic dam in the Montana badlands was one of FDR's most ambitious public works.

After Havre burned down, the best place to build was under the ashes.

Make it an offering.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

A bronze replica of half-consumed salt lick honors a quirky town tradition.

An obscure waterfall that looks like something out of a fantasy novel.

Site of the greatest known waterfall that ever existed.