The world's largest key collection features keys to the White House, Frankenstein's castle, and Hitler's bunker.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

Submerged lava formations create incredible waterworks.

A once-glowing grotto at the bottom of Waikapalae Wet Cave.

This industrial area was the dumping ground for massive amounts of trash, some of which washes up as tiny bits of sea glass.

Doris Duke's lasting collection of Islamic Art, hidden in a Hawaiian paradise.

A 1920s speakeasy that had rum runners racing up and down the shores of California.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

A comprehensive collection of Pez dispensers.

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

Neoclassical Revival mansion and set of horror cult classic Phantasm.

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

This grinning pup statue is all that's left of what was once a ubiquitous Bay Area diner chain.

A 140-year-old castle with underground caves hidden in San Francisco.

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

This one-block alleyway is stuffed with street art that is colorful, cultural, and intensely political.

This shop specializes in oddities and Victorian-inspired wonders.

This surreptitious shop is only open five hours per week.

Playable, historic pinball machines fill this Alameda museum.

San Francisco's oldest operating hotel, with a Victorian atmosphere and a "haunted" fourth floor.

A still functioning vaudeville carousel that has operated for over a century boasts a colorful menagerie and past.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

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

A brooding mansion of clinker brick stands out among the Victorian houses of Pacific Heights.