"The most colorful grottoes of the world.

Beautiful portraits of the artist's children and his amazing stained glass windows in the Art Nouveau style.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

Seven dragon statues—including one that breathes real fire—are scattered throughout the streets of Krakow.

Inside this Krakow church, an explosion of psychedelic color.

Real bones which are said to have belonged to a Polish dragon.

Beloved children's TV characters freckle the German city's streets.

This historic stone bridge has an entire neighborhood clinging to its sides.

The final resting place of one of Germany's most accomplished Renaissance men.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

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

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

The history and future of cannabis.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Museum preserving torture methods from the past.

This vast collection of smoking pipes from across the world spans centuries.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

An intricate and amazing house built by architect Karl Junker.

This ornate Weser Renaissance house was also the home of an infamous witch hunter.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Believed to be the longest railway bench in the world.

According to a satirical conspiracy theory that persists today, this German city of 300,000 is a hoax invented by the CIA.

The bones of the Biblical Magi traveled to Constantinople and Milan before landing in their current home inside an elaborate golden reliquary in the Cologne Cathedral.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.