A giant donut stands as a popular symbol of Los Angeles iconography.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

A nature and cultural preserve named for its multitude of petroglyphs carved by the Northern Sinagua people.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

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

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

The second-largest giant sequoia in the world.

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

The White House Situation Room was taken apart in 2006 and shipped to the Ronald Reagan Presidential Library.

This park is home to California's first oil boomtown, with structures that have stood for more than a century.

This remote river crossing was a popular campground on American westward expansion trails, and a former Pony Express station.

This canyon is named for a unique geologic formation where the river vanishes underground near the mouth of the canyon and reappears farther down.

The world's largest mineral hot springs is home to a herd of bison, a free public bath house, beautiful mineral formations, and a terrifying swinging bridge.

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

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

This large, castle-like structure is hidden amid the mountains on the grounds of the Utah State Hospital.

The largest wildlife crossing in Utah allows local fauna to safely traverse the six-lane Interstate 80 at Parleys Canyon.

This set of three large, volcanic hot springs is a favorite haunt for intrepid divers.

Despite its name, this route in southern Utah offers a heavenly day trip.

An absolutely beautiful 200-foot stained glass installation traces the evolution of knowledge.

Come for the speed, leave in love with the desert.

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

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

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