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

Explore 10 acres of environmental sculptures.

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

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

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

Hidden in the hills of Hollywood, this secluded Oz-themed garden is dotted with dozens of thrones.

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

Olfactory delights in San Francisco's Botanical Gardens.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

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

Venue for strange sideshow displays and musical acts.

Towering basalt columns, a creation of fire and ice.

A hand-built folk art installation covered with messages of God's love.

One man's homage to the sun continues to grow like a glass fractal.

It should come as no surprise that the best view of the Hollywood sign is from Batman's lair.

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

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

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

A psychedelic labyrinth on the San Francisco bay.

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

An artsy hidden staircase leads to breathtaking views of San Francisco.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

A huge musical instrument played by the ocean.