A geological mystery on Camelback Mountain.

The United States Capitol's former columns still stand.

Home to items never before seen by the public.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

At 207 feet, one of the world's longest continuous escalators.

A museum dedicated to the history and exploration of both popular music and science fiction.

A popular European tradition makes its way to the states on one of America's most famous bridges.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Visit the monolithic tomb of America's most famous general.

A semi-scholarly approach to sex.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

The century-old bell and clock tower at UC Berkeley is the third-tallest in the world, and has fossils.

A 90-acre park on former landfill that hosts an annual kite festival.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

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

A man-made island in scenic San Francisco Bay.

This private residence was the template for one of the most beloved television homes of all time.

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

From the Difference Engine to the Cray-1, all under one roof.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Commonly referred to as the most photographed Victorian home in the United States.

On a barren hillside in the Yucca Valley, the recently restored Desert Christ Park has attracted pilgrims and kitsch hunters for over 50 years.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.