Hans Christian Andersen for the postmodern world.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

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

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.

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

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

The library's graceful rotunda is like a bibliophile's temple.

Stockholm's last remaining paternoster elevator.

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

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

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

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

The narrowest street in 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.

A glamorous hotel that once accommodated French resistance fighters and concentration camp survivors.

A museum dedicated to linguistics, from how babies learn to talk to endangered and extinct languages.

The Argonaute submarine was the French navy's pride and joy in the 1950's.

This Paris art space celebrates the creativity and ingenuity that springs from abject poverty, especially in Africa.

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

A French artist's vague warning hangs over Belleville.

Indents in the pavement are all that remain from a grisly death machine in Paris.