These subterranean storage areas hold emergency water reserves.

World War II-era Nazi compound nestled in the Santa Monica hills.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

A very big rock just plopped down in the New England woods.

The world's longest known cave system.

Potential high level nuclear waste storage site for the next 10,000 years and beyond.

The site of one of the strangest disasters in history—a wave of deadly molasses traveling at 35 mph.

An eccentric inventor's castle home with its own indoor weather system.

Friction between grains of sand cause a curious "singing" sound.

Two thousand artifacts from around the world collected by one woman who loved to travel.

Watch the newest land on the planet form before your eyes.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

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

Antiques by the Bay.

Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

An vast warehouse of everyday treasures in Berkeley, CA.

The restored and active Victorian-era final resting place of San Francisco.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A library built during San Francisco's pioneer times is a student's retreat, bibliophile's sanctuary, and chess player's delight.

Museum dedicated to the preservation of surf culture.

A monument to the love people have for their pets.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

Where NASA's satellites and rovers phone home.