Colorado’s second largest natural lake was created by a landslide.

This National Natural Landmark is one of the best examples of a “mass wasting” in the world.

Take a self-guided tour through one of Colorado's most elevated mining districts.

A fake mine that was made using real mining techniques which is also used as a community center.

The temporary burial site of the man who shot and killed Jesse James.

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

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

Most of this “research national monument” still lies buried beneath the earth.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Legends surround this jagged rock formation in the New Mexico desert.

The hallowed remains of a 900-year old Ancestral Pueblo great house.

This spectacular track has run continuously since 1882.

A hotel with a rich Wild West history of miners and bootleggers.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

A renovated hotel is bringing new life to a nearly-abandoned mining town in Colorado.

The largest source of fossilized insects anywhere.

No one knows exactly how deep the world’s deepest geothermal hot spring is.

Long before guestbooks and hotels, frontier travelers signed their names on this rock face.

The first declared National Monument in the United States.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

Yes, this monument is aware that it is about 20 miles away from the actual center of the United States.

Hidden behind Lincoln's head is a chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Abandoned businesses, homes, and rusted cars are all that remains of this stopover town.