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

Guns that have been defending San Francisco since 1904.

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

The only visible piece of San Francisco's most famous shipwreck.

A man-made island in scenic San Francisco Bay.

A promotional sun clock on the site of San Francisco's great raceway.

Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.

Golden Gate Park's historic collection of plants.

This turn of the century masterpiece has a mysterious goaty interloper.

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.

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

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

San Francisco's newly reopened hands-on science museum.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

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

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

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

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

The only theatre in the world constructed specifically for sound movement.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.

A winding path built in secret on the edge of the continent.

A giant Troll lurks under one of Seattle's oldest bridges.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.