Op-art architecture designed for happiness.

A silly medieval mural preserved on the side of a Viennese house.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

A mechanical clock built in 1914, with a rotation of 12 historical figures on its face.

From Ancient Rome to WWII, Neupfarrplatz has over 2,000 years of history underneath its main square.

This riverside restaurant has been serving customers since 1146.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

Nicolas Schöffer's massive interactive sculpture was assembled in 1961 and brought back online in 2016.

This historical Netherlands fortress still bears the marks of its single siege.

Incredible labyrinth of man made caves.

This Corsican Neolithic site is full of pre-Roman megalithic structures that may or may not be penises.

Once known as one of the finest tourist railways in Europe.

On the shores of Lake Laffrey, a monument commemorating one of Napoleon Bonaparte's most compelling victories.

Oldest Museum of the Netherlands is a true cabinet of curiosities.

This towering church is home to a world-famous organ and a treasure trove of medieval art.

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

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

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

This Welsh village gave itself a ridiculous name in a publicity stunt a century ahead of its time.

This tree was grafted from the actual tree that led Isaac Newton to ponder the theory of gravity.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

Europe's first floating restaurant is home to a hilarious legend.