A 19th-century cabin built into a hollowed-out Sequoia tree.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

This small shack near the entrance to Sequoia National Park has been in almost continuous operation for the last century.

A dwindling menagerie of anthropomorphic oil derrick animals still dot the barren California landscape.

This hidden fire lookout offers spectacular views of Sequoia National Park.

This Gold Rush ghost town was once the subject of a territorial dispute between California and Nevada.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A natural dome made of volcanic glass in Inyo National Forest.

Towering basalt columns, a creation of fire and ice.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

This Oakland fairytale kingdom, fiercely devoted to childlike whimsy, was an early inspiration for Disneyland.

A gap in the concrete has been transformed into a miniature playground for the mind.

One man's prolific, decade-long quest to turn trash into artistic treasure.

A private home built to resemble the shape of a microscopic creature.

A huge musical instrument played by the ocean.

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

Art from the latest counter-culture; kids who dye their hair blue and believe the future will be a post-apocalyptic water world.

One of few lasting examples of the brief octagon craze that developed into folly.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

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

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