A modern mechanical planetary system, part of a 10,000 year clock.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

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

A collection of 20th-century automata, penny arcade games, and musical contraptions.

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

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

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

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

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

Olfactory delights in San Francisco's Botanical Gardens.

Its buzzing collection honors vibrator history.

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

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

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

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

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

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

This grinning pup statue is all that's left of what was once a ubiquitous Bay Area diner chain.

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

What began as an illegal art installation has become a symbol for unity, ocean awareness, and coastline preservation.

The oldest structure in a beachside California city was built to serve eight students.

These unusual houses look like giant boats that washed ashore on a residential street.

This unique sanctuary invites you to interact with the beautiful birds.

This little blue house pokes out over the campus of UC San Diego, seven stories high.