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

Once a dining hall for boarding school students, this lodge was a popular haunt for nuclear physicists working on the Manhattan Project.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

This sidewalk tribute honors Colorado's great culinary creation.

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

One lonely, modern pyramid has gone from corporate think tank to deserted boondoggle.

Isak Heartstone, a 15-foot wooden troll made out of recycled materials.

The first transatlantic wireless signal was received at this 17th-century fort.

Hike the unusual hoodoos and rock formations that form this little-known natural wonder.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

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

This historic national park is covered in the stunning ruins of red rock pueblos.

The former home of the army detachment that captured Geronimo.

This church on a Tohono O'Odham reservation has stood since 1797.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

A couple turned their front yard into an artistic masterpiece.

This futuristic bridge is one of the longest self-anchored pedestrian bridges in the world.

An inconspicuous footbridge beloved by San Diego locals.

One of the few remaining carousels built by master amusement park carver Charles I.D. Looff.

One man's quest for the ultimate road trip vehicle.

Swarms of butterflies cannot compare to the awe inspired by the publicly-funded nakedness once displayed in this sunken garden.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.