An invitation-only museum of items natural and bizarre, arcane and exotic.

Gold Rush-era tombstones line the park's paths.

One of the last remnants of the city's Chinese nightclub scene is now a dive bar selling killer mai tais.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

One of the oldest producers of hand-folded fortune cookies still uses its original secret recipe.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

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

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

A psychedelic labyrinth on the San Francisco bay.

A huge musical instrument played by the ocean.

Guns that have been defending San Francisco since 1904.

This sailor's boneyard was lost under a parking lot for decades before being rediscovered.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

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

A modest reminder of treacherous waters at the Golden Gate.

Thirteen trees representing the original thirteen colonies were planted with soil from historic Revolutionary battlefields.

A winding path built in secret on the edge of the continent.

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

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

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

A 300-ship graveyard, with a few still visible at low tide.

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

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

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