A stoic rock cairn is all that remains to remember one of the more brutal instances of frontier treachery in American history.

The high point on the 16th president's eponymous roadway is marked by a massive version of his head.

A popular rock that acted as a waymarker for American pioneers.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The first declared National Monument in the United States.

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.

An antique narrow gauge railway line still running through the Colorado and New Mexico mountains.

Victorian "Fancy Craft" Hair Wreaths and Relics.

There are eight natural springs around town, each with a slightly different taste.

Hidden beyond a kitschy giant beetle is this remarkably sprawling collection of preserved insects.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

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

This Boeing KC-97 tanker is now a restaurant for aviation lovers.

The largest source of fossilized insects anywhere.

This spectacular track has run continuously since 1882.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

The largest self-built castle in the U.S., six decades in the making.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

A small flooded ghost town with a few scattered structures remaining.

The remains of this early 20th century refinery loom on a mountainside like a graffiti-covered fortress.

This geothermal hot spring hides beneath a slowly growing mineral dome.