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

The Guinness Record holder for largest hedge in the world is a verdant Scottish bulwark.

A six-ton wedding present for the King of the Scots.

A magnificent, iconic stone tower in the Scottish Highlands.

Protecting the dead from opportunistic body snatchers.

The final resting place of soldiers' loyal canine companions.

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

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The oldest working mechanical clock in the world.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

A winding, blood-red tunnel of hardened lava navigable by foot.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

Sweden's "good old days" painstakingly re-created in a model village.

It houses the remains of a 17th-century version of the Titanic.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

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

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

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