Home of the Large Hadron Collider and the birthplace of the World Wide Web.

This early version of the guillotine was used to execute the man responsible for its construction.

Remnants of the 16th-century defensive wall still stand unassumingly within Edinburgh.

Metro station with a claim to rock n' roll fame.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Where once there was a train station bathroom, there is now this German burger joint.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Blitzkrieg bop your way through Berlin's Ramones Museum.

One of downtown Berlin's last reminders of its Communist past.

Cold war icon and onetime "hole" in the iron curtain.

Museum dedicated to the terror regimes of Hungary.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Apartment complexes built into huge repurposed natural gas tanks.

One of the best collections of wax anatomical models in the world.

Macabre museum devoted to historical Viennese murders.

This former insane asylum now holds a pathological anatomy museum.

The final resting place for the remains of 143 Habsburg royalty.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A museum in the childhood house of a medical pioneer.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.