Located in an old church, this brewery produces a different kind of holy water.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

One time home to turn of the century explosives, now hidden under the Bay Bridge.

This print shop boasts one of the largest pinball arcades in San Francisco.

This 19th-century church is now a popular roller rink.

This private residence was the template for one of the most beloved television homes of all time.

The remains of a ruined mansion memorialize the 1906 earthquake.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

A huge musical instrument played by the ocean.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

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

The haunting beauty of this little-visited wreck makes it a true hidden treasure.

A giant interactive periodic table with real samples of the elements.

The oldest garden in Prague, once part of an medieval orchard.

To the famous surrealist artist, liberty required two torches held high.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

France's Lilliputian park displays over 100 of the country's monuments for visitor perusal.

One woman's decades-long obsession with the "La Fée Verte."

A charming flea market shop dedicated to retrofuturistic apparati.