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

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

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

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

This abandoned boat was left in place thanks to its rotting beauty.

A tribute to the life and work of the beloved "Peanuts" cartoonist.

St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

A community of collapsing homes more than a mile out from the Florida coast.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

Former villa and estate of James Deering developed to preserve native tropical forests.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

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

San Francisco's newly reopened hands-on science museum.

Of all the origin stories for weed's secret code, this one likely has the goods.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

Guns that have been defending San Francisco since 1904.

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

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

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

A living time capsule of the 1960s Richardson Bay water-front.

Discover for yourself what Herb Caen referred to as "the best kept secret in the Bay Area."

This infamous prison has a store where you can buy goods crafted by incarcerated people.