This cave holds a surprisingly colorful variety of geological oddities.

Prayers and messages of hope decorate the ceramic tiles of this pavilion.

A large circus museum with summer performances.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

An enormous, inside-out glass globe built in 1935.

Golden Gate Park's historic collection of plants.

In the ruins of Glastonbury Abbey lies the alleged resting place of the legendary king.

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 tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

This elaborate towering structure was once famed for its revolutionary height.

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

A rare view of a preserved Victorian science museum.

Literally a million fascinating cartographic artifacts are held in this sprawling university collection.

These molds for fiberglass statues have formed an eerie, accidental sculpture park.

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

An vast warehouse of everyday treasures in Berkeley, CA.

The show's fictional Korean medical camp was created in the Santa Monica hills.

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

The haunting ruins of Jack London's dream house.

Concrete strongholds stand guard over the Golden Gate.

The interior of the Overlook Hotel in "The Shining" was based on this Yosemite original.

Internationally-recognized arts center housed in a century-old former military barracks.