An architect's childhood fantasy treehouse made real.

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

A beautiful geyser under environmental threat.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A memorial to the most decisive Native American victory of the Plains Indian War.

A scenic natural bridge with a creek running underneath.

The only retired U.S. nuclear missile silo that is open to the public.

The same security that protects our nukes accidentally protected a gentle herd of antelope.

Colorado's only active volcano last erupted around 4,000 years ago.

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

This razorback ridgeline has doubled as a scenic drive since the early 1900s.

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

An unexpected alley with light shows and nature views.

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

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

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

These tall, red sandstone pinnacles outside Moab are often forgotten amid their more famous neighbors.

The fifth-longest natural arch in the world, and the longest outside China.

This interpretive path lets you get up close and personal with dinosaur bones.

Explore a wealth of fossils in one of the most prolific dig sites in North America.

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

The moving metal works of one troubled artist can still be viewed on his front lawn... for now.

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

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