Each winter this underground cave forms a dazzling ice palace.

The mysterious round rocks of Schooner Gulch.

This whimsical seashell-shaped place of worship was designed to blend into its surroundings.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

A replica that won't float away.

Every Christmas, one Arizona city makes the most of its dry climate by creating an arid desert tannenbaum.

This memorial includes fragments from one of the greatest tragedies in United States history.

A colorful, century-old cemetery of the Yaqui Indian Tribe hidden amid the suburban sprawl of Tempe, Arizona.

A stealthy Apache hideaway that became the haunting site of a mass grave.

Built by the inventor of the radio, this abandoned hotel has housed early radio employees, military men, and a dangerous cult.

Believe it or not, this is the final resting place of the man who created the Odditorium.

Hidden inside a gift shop that doubles as a museum, this gargantuan yo-yo can only be operated by crane.

California's own majestic geyser is powered by a subterranean volcano.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

The haunting ruins of Jack London's dream house.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

Secret Manor, a house full of legends, the least of which is the haunting of long-deceased ladies of pleasure.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.

Tenacious mummies survived dental problems, eternal entombment, and more than their fair share of devastating fires.

The remains of a 12th-century chapter house in Golden Gate Park.