Abandoned silver mine strewn with wrecked and twisted structures.

When ecosystems collide in the arid Southwest.

A preserve with 75,000 ancient drawings remains the realm of public – not just scientific – exploration.

These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A clear blue swimming hole with hidden caves, still unexplored.

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

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.

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

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.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

This giant temperature attraction created some giant electric bills.

Honoring the famed folktale author, this California museum looks like it belongs in the Black Forest.

Scores of vintage street lamps shine along L.A.’s Miracle Mile.

A man-made island in scenic San Francisco Bay.

An extraordinary final resting place full of oversized art, amazing statues, and dead celebrities.

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

This private residence was the template for one of the most beloved television homes of all time.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

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

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