Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Canyon walls shrouded in ferns.

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

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Quite simply the largest tree in the world (by volume).

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

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

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

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

Towering basalt columns, a creation of fire and ice.

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.

The rocks in this arid basin leave trails of movement behind them.

A trash dump made beautiful by nature's power.

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

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

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

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

A huge musical instrument played by the ocean.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

Owned by Native American women, this brewery is a celebration of indigenous culture in the American Southwest.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.