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

A world-class observatory in the California desert.

Where there's quartz, there must be gold. Thus is the story of the mines of Julian, and the titillating times of the Gold Rush.

A house built from trash known as the poor man's Hearst Castle.

"Only the devil could play golf here."

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

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

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

The first declared National Monument in the United States.

Continuing the tradition of the dime museum in style.

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

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

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

This Canadian monument to the man who invented the telephone allows visitors to get up close and personal with the artifacts of his life.

From the Difference Engine to the Cray-1, all under one roof.

Guns that have been defending San Francisco since 1904.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

The interior of the Overlook Hotel in "The Shining" was based on this Yosemite original.

Towering basalt columns, a creation of fire and ice.

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