Sweden's oldest animated sign is still lighting up the skyline today.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

Stockholm's tiniest statue is of a small boy looking at the Moon.

Stockholm's narrowest alley is barely over two feet wide.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Sweden's "good old days" painstakingly re-created in a model village.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This bridge was constructed from the rubble of the infamous Bastille.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

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

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

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

The narrowest street in Paris.

The first green space constructed on an elevated viaduct.

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

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

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

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

France's most famous cemetery, with some of its most curious tombs.

The first woman to become a member of the parliament of Iceland.

Twisted girders are all that remain of an Icelandic bridge that was wiped out by a combination of volcanic heat and glacial floods.