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

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

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

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

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

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

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 Saint Nicholas-themed ghost town in the Mojave desert.

This historic Victorian hotel has a scandalous history of affairs and murder.

Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

This small interfaith chapel lies not far from the rim of the Grand Canyon.

The only surviving prototype for Buckminster Fuller's house of the future.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

A massive volcanic plug is now a protected area that hosts a number of bird species.

The unbelievably opulent home built for an infamous newspaperman.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The ghostly remains of an accidental sea.

Oldest building in California still in use.

The quiet canyon has a tumultuous history involving a doomsday cult.

Abandoned bridge hidden deep in the San Gabriel Mountains.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

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

Hollywood's oldest hotel is the site of the first Academy Awards, the birthplace of Marilyn Monroe's career, and the home of Montgomery Clift's ghost.