Amsterdam's former hotspot for public executions and dissections.

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.

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

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

A field of nothing but boulders which resembles a giant's gravel driveway.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

The video game-themed street art first popped up in the French city.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Abandoned railway line circling the city of Paris.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The celebrated eyesore created by starry-eyed sweethearts.

Paris' linguistic guide to the international language of, yes, love.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Be on the lookout for the symbolic insect all over the city.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

This small record store was a favorite of Oasis's Noel and Liam Gallagher, who mentioned it in one of their early songs.

Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.