Volcanic rocks ground down into sand make this Spanish beach as black as night.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

A former plague hospital turned medical museum.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

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

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

A restaurant and observation deck built in a unique broadcasting antenna.

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

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

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

This Luxembourg cave is covered in cryptic looking marks left by mining activity.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

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

Terrifying derelict military hospital once housed a recuperating Hitler.

This former steel and coal plant is now a neon-lit industrial fantasia.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

The fairy tale castle of the "fairy-tale king."

The ruins stand as a somber reminder of France’s worst civil catastrophe of the 20th century.

A fortress on this island housed the mysterious prisoner known as the "Man in the Iron Mask" for more than a decade.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.