St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

A mental health hospital dating back more than 139 years, now features a museum.

In the middle of a suburban Denver neighborhood is a cave that once provided solace for a prominent Ute chief and his family.

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

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

The remains of the dam that unleashed a 15-foot wall of water on Denver.

Small teepee-like houses built for TB patients have become sheds, studios, and bus stops around Colorado Springs.

An impressive collection of over 50,000 minerals including moon rock from the Apollo 17 mission.

The largest dinosaur trackway in North America is tucked away among this canyon's ghosts and archaeological gems.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

A small horde of mythical creatures lurk almost imperceptibly within the museum's wildlife dioramas.

A downtown park built on top of unclaimed graves.

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

This spectacular track has run continuously since 1882.

The clock that sets them all.

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

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

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

At the tallest peak in Colorado, an electrifying mix of thin air, lightning, and rivalry.

The largest source of fossilized insects anywhere.

A little-known hot spring haven right below the highway.

The world's largest carnivore sanctuary is home to over 450 meat-eating rescues.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

Silver in the hills led to the speedy creation of this boom town and a lack of it saw the town abandoned nearly as quickly.