The world's first purpose-built motor racetrack was destroyed by the outbreak of two world wars.

Rusted cars, trucks, and buses form a fascinating collection of Soviet-era machinery.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

The remains of Alfred Nobel's first nitroglycerine factory can still be found on the shores of a Swedish bay.

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

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

An eerie, derelict amusement park in Berlin.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

You can spend the night in Dr. Frank-N-Furter's castle.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

Pop culture has helped to keep this iconic British building from being destroyed.

Hear the quietest sound from across the dome.

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

A hands-off space for graffiti artists to hone and display their skills.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A kaleidoscopic warehouse-maze of handmade neon signs.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

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