This lucky bronze frog was gifted to Madrid by a casino.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

A lush indoor jungle fills this bustling Madrid transportation hub.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

One of the most easily accessible examples of the rare 1960s UFO houses.

The footprint of a frustrated devil in Munich's Cathedral.

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

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

This historic Amsterdam bar used to accept sailor's monkeys as payment.

A curious collection dedicated to human and animal anatomy and pathology.

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

The world's only museum devoted to the wonders of fluorescence.

This recently restored crypt was once plagued by liquefying coffins and exploding caskets.

Head underground and take a tour of the city's working sewer system, and see the underground river Senne, which defined Brussels for centuries before being covered in the 19th century.

Meet the bronze beloved pet to a family of famous peeing statues.

The Devil’s own choice when he needs a drink in Brussels.

The house that took a plunge into the facade of a museum.

Apartment complexes built into huge repurposed natural gas tanks.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

Collection dedicated to funeral rites, equipment, and mourning rituals of the Viennese.

The townhouse where the "Blood Countess" Elizabeth Báthory started her murderous career.

This museum promotes informed contraception by documenting its often secret past.