This mysterious runestone embedded in a church wall is linked to the medieval cult of Saint Erik.

Ancient burial grounds of the wealthy.

The first thermometer made with the almost-universal temperature scale is backwards.

The second-largest collection of runic calendar staffs in Sweden.

The second oldest anatomical theater is housed in a museum of curiosities.

The final resting place of the father of modern biological taxonomy.

Legend has it this spring formed at the spot where a medieval Swedish king was killed.

Uppsala's adorable feline sign celebrates a popular children's book set in the Swedish city.

A large collection of ancient runestones decorates this university courtyard.

A rare rune stone dedicated to a woman.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

A statue honors the children who fought Nazis in Poland.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An enormous and lavish Gothic church in Czechia.

A church of bones, decorated with 40,000 human skeletons.

A monument commemorating the 852 lives lost in the sinking of the MS Estonia.

Shop at the 200-year-old store where Julia Child stocked up on copper cookware.

Marvel at the opulent Art Nouveau interior while dining on dirt-cheap French classics.

Order a boozy baba au rhum at the oldest patisserie in Paris.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

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