Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Op-art architecture designed for happiness.

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

Legends surround an ancient tree trunk riddled with nails for good luck.

Baroque celebration of the end of the Great Plague of Vienna.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

The beautiful baroque library of the Hapsburg empire.

Along the edge of this fountain are 365 smaller fountains that represent the days of the year.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

The Habsburgs' royal collections of art and wonders.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

An ornate private entrance to the Vienna subway built specifically for the emperor.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

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.

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.

Mountain where Jesus was first tempted by the Devil.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The world's oldest bookshop still in operation.