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

The largest source of fossilized insects anywhere.

A multicolored mineral mound dribbles piping hot spring water right off the side of a highway.

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

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

This spectacular track has run continuously since 1882.

Gleaming self-built castle towers made from beer cans and inspired by "Vitamin Mary Jane."

Three witches are said to be buried beneath these unmarked concrete graves.

All that remains of this abandoned coal town is a beautiful, haunting cemetery.

The oldest continuously occupied public building in the United States.

A small side chapel in Santa Fe's basilica is home to the oldest statute of the Virgin Mary in North America.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

Home to New Mexico's longest bar, this watering hole also has a mining museum and a haunted history.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

When ecosystems collide in the arid Southwest.

A short but powerful waterfall resides amid Colorado’s Great Sand Dunes.

This super steep hike ascends 2,000 feet in less than a mile.

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

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

An unexpected alley with light shows and nature views.

Victorian "Fancy Craft" Hair Wreaths and Relics.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

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