Neon artworks light up this dark Edinburgh tunnel.

This king penguin is a knighted brigadier of the Norwegian Army.

Now home to a drinking establishment, this building has a macabre history.

Long abandoned underground complex to keep royals safe from a nuclear war that never came.

This 16th-century house tells the city's history through old artifacts and quirky tales.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

An American ghost town hides along a side street in Scotland's capital.

This allegedly haunted 16th-century tower house-turned-museum exhibits thousands of spectacular objects.

A 18th century graveyard and its astonishing cortege of macabre iconography.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

This series of Scottish caves has no clear purpose other than baffling historians.

360° views of the city plus five floors of optical illusions and hands-on science.

The fountain marks the area where hundreds of accused witches were burned at the stake.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This permanent collection of preserved bodies taken from Irish bogs is one of the leading authorities on such morbid mummies.

An early Portuguese serial killer's head is alarmingly well preserved in a jar at the University of Lisbon.

A garden in Lisbon filled with giant porcelain creatures.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

This unassuming bookstore in the heart of Madrid is one of the oldest in Spain.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

Puppet theater and museum holding a collection of more than 300.

From Iggy Pop to David Bowie to Nick Cave, this regal music studio has served some of the all time greats.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.