This large, circular tomb is the final resting place of the first emperor of Rome.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

At the time of its completion, it was the tallest dam in the world.

A small town built on an abandoned airfield has former runways as streets and a bar and grill in an old airplane hangar.

A devilishly named gorge that was a sign of salvation for many pioneers.

A popular rock that acted as a waymarker for American pioneers.

Surrounded by a hundred mile radius of billboards, Little America is a roadside attraction whose primary appeal is hospitality.

A small Wyoming town is home to the state's oldest-operating soda fountain.

Long before guestbooks and hotels, frontier travelers signed their names on this rock face.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

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

Native Americans built this circle of stones, which was used to predict astronomical events.

The remote outlaw hideout of Jesse James, Butch Cassidy, and the Sundance Kid.

An architect's childhood fantasy treehouse made real.

One man's ambition created this psychedelic log home.

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

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

A remnant of the last Ice Age, this lake is surrounded by fascinating rock formations.

Over thousands of years, this slot canyon was carved out of the bed of an ancient lake.

This circus town museum recognizes the outstanding clowns of history.

This unique zoo is the only place in the world where you can see all 15 species of crane.

The remains of a enormous earthen figure of unknown origins cuts across a rural Wisconsin road.