A coal fire has been burning underground here since 1896.

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

It takes a nine-mile hike to reach these hot springs, but weary hikers are rewarded with stunning views and a warm soak.

This naturally-sourced hot spring is now home to a clothing-optional resort.

The first railway tunnel to cross the Continental Divide and, at 11,523 feet, was once the highest railroad tunnel in the world.

All that remains of this once-booming mining town are the ruins of a saloon.

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.

This 19th century jail was mainly used to incarcerate the drunk and disorderly.

This nearly abandoned town was once a thriving mining community until a series of fires.

The highest bridge in America was built for an almost unnervingly small amount of money.

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

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

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

This Colorado hiking trail provides a small gold mine of abandoned gold mines.

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

Inside this shop, visitors are treated to a unique blend of natural history and art.

A lively annual event in which thousands of people race to push coffins heavy with bodies up a hill.

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

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

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

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

The largest source of fossilized insects anywhere.