When zealous marijuana enthusiasts kept stealing the "Mile 420" highway marker, the State of Colorado got creative.

The world's largest key collection features keys to the White House, Frankenstein's castle, and Hitler's bunker.

The largest source of fossilized insects anywhere.

Colorado's only true geyser is hidden within the San Juan National Forest.

Where scientists keep miles of very valuable ice from Antarctica and Greenland from melting.

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

The childhood home of Henry Jones Jr. is now an adventure-themed bed and breakfast.

Wall to wall taxidermy at Denver's oldest and most exotic steakhouse.

Rather than a run-of-the-mill franchise hotel, this lodging has been decked out in dinosaur decor.

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

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

This spectacular track has run continuously since 1882.

Despite being one of the most photographed vistas in the Rockies these twin peaks are rightfully known as the "Deadly Bells."

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.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.