What is the Thing?

America's only nuclear missile silo open to the public.

A scrap-metal sculpture recalls an infamous 19th-century camel.

This memorial pyramid marker honors one of the United States Government's first official camel riders.

Ancient pueblos built into the base of a natural canyon wall.

This historic national park is covered in the stunning ruins of red rock pueblos.

These elusive, isolated rodents evolved into a distinct, locally iconic subspecies.

This isolated outpost was once the only place to cross the Colorado River for hundreds of miles.

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

See massive fossils that are over 200 million years old in northeastern Arizona.

This abandoned bootleg attraction was built to cash in on the popularity of classic TV show, F Troop.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A 19th-century cabin built into a hollowed-out Sequoia tree.

Quite simply the largest tree in the world (by volume).

Four hundred granite steps were built into this massive rock by the National Park Service.

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This quiet park's strange sedimentary spires were named after Kodak's color film.

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

A striking, menacing sandstone peak towering above a landscape that's equal parts Mordor and the Moon.

Within the former ghost town of Cisco is a carefully restored tiny town with one resident and its own art residency.

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

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.