Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Playable, historic pinball machines fill this Alameda museum.

A large instrument played by the wind.

The world's most famous donkey lives in this pen.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

Bizarre Cavern.

This German version of Universal Studios holds a vault of treasures from the NeverEnding Story.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

A toxic ghost town sitting atop a massive coal fire.

A B&B on a Victorian lighthouse station in San Francisco Bay.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

This experiment in the lifespan of seeds will take a century before it is complete.

A walk down memory lane in the heart of one of San Francisco's most notorious neighborhoods.

This historic toy museum brings a little whimsy to a city not usually remembered for such things.