The remains of a 12th-century chapter house in Golden Gate Park.

A garden oasis filled with flowers mentioned in the works of William Shakespeare.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

San Francisco's first World's Fair, dedicated to the wonders of California.

A masterpiece in Golden Gate Park by virtue of the artist’s debt.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

A quiet marker in memory of local men and women lost in WWI.

Under the shadow of its towering parent tree, a rare specimen of sequoia produces ghostly white leaves.

Part mural and part sculpture, this work of art sits in the middle of the Promenade, as if swimming in a river of asphalt towards the ocean.

Thirteen trees representing the original thirteen colonies were planted with soil from historic Revolutionary battlefields.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

A monumental cross hides in the trees in Golden Gate Park.

The remains of a ruined mansion memorialize the 1906 earthquake.

The final resting place of the Emperor of the United States and Protector of Mexico.

A vast city of the dead, where the deceased outnumber the living by more than a million.

The peaceful gravesite of a rugged wild west gunman echoes the touching story of his last days.

A bronze tribute to a legendary Californian, the self-proclaimed "Emperor of the United States."

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

This unique formation appears as though an asteroid landed on the forest.

A classically inspired temple in Redwood City.

Today's aerospace industry can be traced back to one man and his gliders.

A giant chess set, minus the psychedelic drug trip.

Three plaques mark the spot where the "forgotten father of broadcasting" worked.