The source of America's longest river is also a historical landmark and the start of a famous nude run.

The old fire tower is one of the last of its kind in the United States.

The shortest river in America flows for just 201 feet.

At 11,500 feet in elevation, there is no toilet in the state closer to the sky than this one.

These free-roaming horses were once destined to disappear from the land.

This natural wonder is disappearing at an alarming rate.

In 1909, the steepest and most difficult piece of track on the Canadian Pacific Railway was replaced with a series of spiralling tunnels cut into the mountains.

Fossils, railroads, and waterfalls!

Odd outsider art installations surround a Gold Rush-era ghost town.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Most-visited and most-photographed slot canyon in the American Southwest.

Cockroach Museum features roach celebrities and live hissing cockroaches.

Two massive and unstable sinkholes are yearning to unite, and their consummation could be catastrophic.

Legend says the horned lizard spent 31 years sealed in a time capsule before he was discovered alive.

The man who wasn't there.

Belly up to the bar in Cowtown, don't forget to buy some boots.

The highest point in Texas is capped by a big silver pyramid.

Steep canyon walls hide a forested oasis in the West Texas desert.

In Paris, Texas they have their own Eiffel Tower, it just has a cowboy hat on it.

This downtown Dallas art installation is always on the lookout.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

A modernist landscape of water and sci-fi concrete.