A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

This old-world mansion with lush gardens is a gem in the heart of Silicon Valley.

Abortion, prohibition, religion, war, and fear all play a part in the history of this idiosyncratic Pacifica castle.

The peaceful gravesite of a rugged wild west gunman echoes the touching story of his last days.

This odd little museum holds exhibits on everything from blacksmith equipment to hair jewelry.

Outside San Francisco lies a small clown cemetery and memorial.

The timepiece that exonerated a labor radical accused of a parade bombing that killed ten people.

Two pillars set 10 paces apart commemorate the "last notable American duel."

The perfect spot for a picnic, right next to a giant ballistic missile.

A 1920s home transformed into an immersive art experience, where every room is a portal to another realm.

Over a century old, this restored Victorian building is surrounded by a lush garden filled with rare palms.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

An artsy hidden staircase leads to breathtaking views of San Francisco.

George Lucas donated this park to honor the birthplace of his two biggest movie franchises.

A 140-year-old castle with underground caves hidden in San Francisco.

Frank Lloyd Wright died a year before construction on his largest public project even began.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Guns that have been defending San Francisco since 1904.

Join the circus for a few lessons to learn clowning, acrobatics, and Chinese contortion.

Radioactivity still cause for concern at this urban explorer's paradise.

This print shop boasts one of the largest pinball arcades in San Francisco.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Adolph Sutro's little-known, geographically inaccurate, deprecated monument.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.