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

This modern antique shop is a museum for 1980's Saturday morning cartoon culture.

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

A monumental cross hides in the trees in Golden Gate Park.

A walk down memory lane in the heart of one of San Francisco's most notorious neighborhoods.

Nuclear waste dump site now an environmental sanctuary.

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

Golden Gate Park's historic collection of plants.

This turn of the century masterpiece has a mysterious goaty interloper.

An overlooked and unassuming engineering marvel.

A monument to the love people have for their pets.

A hidden subterranean installation offers a view of the sky.

Visible below the waves are memorials to the city's Gold Rush dead.

Floating man-made island and upscale restaurant.

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

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

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

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

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

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

Furniture tries to escape an abandoned building in San Francisco.

Guns that have been defending San Francisco since 1904.