Once the largest windmill outside of Holland, with enormous 114 foot sails.

This sailor's boneyard was lost under a parking lot for decades before being rediscovered.

The contents of this safe survived a 37-kiloton nuclear bomb.

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

9,000 square feet of vintage and modern mechanical toys, dioramas & sideshow curiosities.

The grand, column-fronted, sculpture-adorned home of the ambitious digital library.

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

The remains of a ruined mansion memorialize the 1906 earthquake.

A huge musical instrument played by the ocean.

The rusting remains of the largest assembled WWII fleet on the West Coast.

An abandoned Cold War missile radar site.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

A modern mechanical planetary system, part of a 10,000 year clock.

A hidden subterranean installation offers a view of the sky.

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

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

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

Visible below the waves are memorials to the city's Gold Rush dead.

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

Over 315,000 preserved amphibians and reptiles in jars.

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

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

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

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