The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

This replica of the Greek structure is in the heart of Nashville.

An optical illusion found amid a logged redwood forest.

The programmatic glory of LA's giant whiskey barrel building has become an upscale reminder of the city's kitschy roadside past.

This massive redwood tree has a hole in the base big enough to drive through.

A house carved into a rock in the 1940s.

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

A museum dedicated to the history and exploration of both popular music and science fiction.

This expansive bridge in the Canadian wilderness was originally just built for friends.

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

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

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The world's longest known cave system.

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

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A sharp bend in a dramatic river canyon cut through red rocks.

Most-visited and most-photographed slot canyon in the American Southwest.

A smoke stack so large, the Washington Monument could fit inside!