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

Its buzzing collection honors vibrator history.

Amsterdam's former hotspot for public executions and dissections.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

A curious collection dedicated to human and animal anatomy and pathology.

A friendly pub with a sordid past in cock fighting.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

A domino effect created with Britain’s iconic telephone boxes.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Collection dedicated to brands, packaging and advertising.

Catacombs turned marketplace.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

Hidden beneath the streets of London is a secret subway that only carried mail.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

A kaleidoscopic warehouse-maze of handmade neon signs.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Sail in for a ’dam good slice.

This cheese shop also houses a museum devoted to Dutch dairy.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.