The design of this beautifully crafted building was inspired by Norwegian glaciers.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world’s largest coastal brick fortresses.

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The last bastion of Roman presence north of the Alps looms over a German town.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

A two-way chairlift system between Zugliget and the highest point in the city.

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

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

Budapest's Communist-era statues, banished to the suburbs.

A museum in the childhood house of a medical pioneer.

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

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

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Nearly 2 billion seeds from 38,000 species are stored and processed at this visitable facility in a quiet corner of England.

This medieval manor house was equipped with secret compartments for hiding priests.

England's most notorious suicide spot.

The forest that inspired Winnie-the-Pooh's Hundred Acre Wood can be found outside London.

This open-air heritage museum illuminates centuries of historic English life from a West Sussex village.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.