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

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Concrete strongholds stand guard over the Golden Gate.

An abandoned, unfinished mansion on grounds strewn with lava rocks.

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

The ghostly remains of an accidental sea.

The only thing stranger than stumbling onto these philosophical musings is the story of the homesteader who created them.

Go inside to really appreciate this 500-year-old technological masterpiece.

Hear the quietest sound from across the dome.

World War II-era Nazi compound nestled in the Santa Monica hills.

A bomb shelter and some fireplaces are all that remain of the house Fred Roberts tried so hard to keep standing.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.

Carved by a waterfall in a hard-to-reach rock formation, this heart-shaped rock has inspired romantics for decades.

Abandoned Air Force base that has fallen into disrepair.

Abandoned bridge hidden deep in the San Gabriel Mountains.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

Experience a charming 1930s version of "infotainment."

The rusting remains of the largest assembled WWII fleet on the West Coast.

World-famous, Pink's still manages to keep its prized cult fetish status.

Bits and pieces from the ill-fated Donner Party's winter cabins.

The Empire Mine is "one of the oldest, largest, deepest, longest and richest gold mines in California."

The bullet-riddled wall from the St. Valentine's Day Massacre, bloodstains enhanced for your viewing pleasure.