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.

This historic Union Pacific Railroad depot is a stunning symbol of American post-Civil War progress.

The same security that protects our nukes accidentally protected a gentle herd of antelope.

The only retired U.S. nuclear missile silo that is open to the public.

A small Wyoming town is home to the state's oldest-operating soda fountain.

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

A roadside attraction filled with an astounding array of gloriously wacky vehicles.

This museum and former department store is home to the largest collection of A.R. Mitchell art in the world.

This memorial pays homage to Pueblo's four Medal of Honor recipients.

This historic stone barn is the former home of legendary cattleman Charles “Lonesome Dove” Goodnight.

Once named the “world’s oldest gas station” due to its unusual construction material.

This small piece of railroad history sits behind the parking lot of a chain grocery store.

Check out a hidden collection of vintage neon signs.

A focal point of in Denver’s skyline for over a century, inspired by a Venetian basilica.

A Rocky Mountain city provides a happy ending for a pinto pony and his Brobdingnagian red chair.

This enigmatic building features numerous architectural styles.

This 19th century jail was mainly used to incarcerate the drunk and disorderly.

The remains of a World War II-era Japanese American internment camp dot a windswept Colorado hill.

This three-mile concrete levee in Pueblo, Colorado was transformed into the world’s longest painting.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.