For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A socialist building dedicated to teachers showcases one of the largest Soviet mosaics in the world.

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

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

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

Tiny memorials honor individual victims of the Holocaust.

The cutest way to stay safe in traffic.

Lumps of significant stone from around the world surround a flaming monument for peace.

When you're a great Russian Tsar, even your vomit gets a statue.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

These steps offer a breathtaking view of one of Europe's most besieged fortresses.

The location of a citizen uprising that led to a gruesome act of mob justice.

A sweet symbol marks the place where torturous executions were once carried out.

A quartet of brightly colored mythical beasts stand sentry at this gateway.

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

A rare and unique example of an 18th-century door latch calls this restaurant home.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

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

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

This sculpture commemorates Edinburgh's sister city and their respective celebrity dogs.