A striking 12th-century-style castle built on the edge of a cliff.

A wunderkammer of mysterious objects and stories.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

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

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

Started as a kitchen garden, now the second largest botanical garden in the world.

The fairy tale castle of the "fairy-tale king."

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An eerie, derelict amusement park in Berlin.

A network of concealed passageways lies within a busy London Underground station.

English antique dealers with a taste for the unusual.

Abstract dinosaur models in London.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.

A collection of comics, graphic novels, animation and caricatures devoted to exploring this often overlooked art form.

A toy store with a century-long history preserves the craftsmanship of playthings of the past.

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

London's old-school healing garden.

This hidden green space is the city's second largest conservatory.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.