In Portugal, a secluded stretch of untouched natural beauty hides at the bottom of a steep hill.

Elaborate tile work in this railway station tells the story of Portugal.

Amsterdam's former hotspot for public executions and dissections.

The world's second largest single-dish radio telescope, once used to contact E.T.

Fantastic views and thousands of love locks.

The castle where Martin Luther secretly translated the New Testament from Greek to German while in hiding.

Tiny castle in the middle of the Rhine made you pay to pass.

Legendary site where an evil bishop was devoured by rodents.

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

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

Twisted buildings adorn the banks of the Rhine river.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

The "Prussian Versailles" that is as glorious today as when it was built.

The prototype for all Nazi concentration camps.

The highest point in Belgium is a staircase to nowhere.

Hiding the longest subterranean river known in the world.

Theme park featuring miniature replicas of European monuments.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

Climb to the top of the world's largest seated bronze Buddha.

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.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

This whimsical statue dumps water on its head to symbolize knowledge flowing into his brain. Or maybe booze.