The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

An unprepossessing storage reservoir in southern Utah has a checkered past.

A stoic rock cairn is all that remains to remember one of the more brutal instances of frontier treachery in American history.

Hundreds of drawings left by the land's previous inhabitants remain mysterious.

Largest collection of mounted dinosaur specimens in the world.

The last SR-71 ever constructed.

The largest island on the great salt lake is home to curious creatures and strange stories.

A Roman-style column in Oregon hides a spiral staircase inside.

An extraordinary mixture of natural beauty and man-made phenomena.

Boise State's stadium was the first non-green football field in the world.

Jail from the 19th century that was built by inmates.

The only bridge in the United States where BASE jumping is legal without a permit year-round.

Where the famed daredevil attempted to launch himself across a canyon in a custom-built rocket.

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

A creek tumbles over a series of step-like rocks to create this scenic water feature.

This rustic old building is said to be the most photographed barn in America.

One of the largest collections of wildlife art in the United States, built into the side of a cliff in rural Wyoming.

This town is home to the world’s largest arch constructed entirely of elk antlers.

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

This erect, phallic geological spire wasn't always named so domestically.

A museum chronicling pioneer life constructed over Interstate 80.

A Mormon place of exile in Missouri.

At a mile long, the Fort Madison Bridge is the largest double-decker swing-span bridge in the world.

Home with Gothic windows featured in a famous painting.