A beautifully eclectic mix of architectural styles.

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

This large copper bolt represents the benchmark for measuring sea levels in most of Europe.

This unattributed sculpture in Amsterdam is hiding in plain sight.

A set of seven houses, each built in a style that represents a European country.

A line number in Amsterdam that will likely never be used again due to its tragic history.

This subterranean studio is filled with fascinating kinetic art.

This pirate-broadcasting-tower-turned-restaurant played a rebellious role in the history of Dutch television.

Sail in for a ’dam good slice.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

This colorful but controversial ceiling has been likened to a 21st-century Sistine Chapel.

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

Inside a former cabaret, seven floors of erotic art.

This lesser-known Frank Gehry building houses a treasure trove of cinema history.

This mural painted by Keith Haring was done without payment as a gift to entertain the children at the Hôpital Necker.

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

This recessed garden protects thousands of mountain plants by creating its own microclimates.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

The former home of France's controversial pop maestro is almost completely covered in ever-changing tributes and graffiti.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

The first green space constructed on an elevated viaduct.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

This Parisian café sticks almost exclusively to an ethos of reuse.