Walk or bike along a narrow strip of Belgium sandwiched by German territory.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

Once a beautiful palace, this structure is now known as the ''museum of destruction."

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

A reproduction of a mysteriously preserved body found in the 18th-century and put on display for years before burial.

The underground sanctuary of a mysterious ancient Roman religious cult contains an exquisite traditional fresco.

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

Lucerne's central prison was converted into a tourist hotel with a bare minimum of changes.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Extensive private collection of authentic Medieval devices used for human torture and execution.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

The Swiss hilltop housed an early 20th-century vegetarian nudist colony.

From buck blood to Theriak miracle tonic, this collection of Renaissance chemist's gear look's like a wizard's pantry.

An Elvis superfan built Denmark's own version of Graceland.

Along this stretch of beach in Denmark resides several massive bastions of energy.

An old Danish political institution where members of government can grab a drink off the record.

A museum filled with tiny, adorable versions of the mighty Royal Danish Navy.

The world's first combination ski slope and power plant.

Built after WWII, the observatory site for the University of Copenhagen exhibits once world-class instruments.

The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

A whimsical sculpture garden right out of a children's storybook.

This secret collection of the strange and occult was rediscovered in a forgotten room of an old house.

Nuclear waste experts study this prehistoric crater lake to envision landscapes one million years in the future.

The mile-long pier stretches from a ruined fortress out into the Baltic.