A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

This cemetery features modernist statues as strange as its name.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Five million people are laid to rest here, more than the population of Madrid itself.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A subterranean display of public art and architecture.

An abandoned train station in Munich constructed for the 1972 Olympic games.

A fearsome dragon clings to a corner of Munich's city hall.

This century-old cinema house has a marquee that has been hand painted by a single man for over 25 years.

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

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

A stairway to heaven, or to nowhere at all.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

The bears of Bern have been a city highlight for over 500 years.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.