This French chateau is home to the world’s largest private collection of fighter jets.

Putting the "mod" in "modular" since 2000.

What if all public housing projects had been designed by "the Pygmalion of modern architecture," not only their prototype?

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

The Bauhaus-style former industrial complex is considered the world's most beautiful coal mine.

Now overgrown, these anti-tank barriers from World War II are sometimes called "dragon's teeth."

A former ironworks that was the first UNESCO industrial site.

Large Hadron Collider and the Birthplace of World Wide Web.

The World Wide Web was created in this nondescript corridor at CERN.

The shape of this old salt factory complex was inspired by the course of the Sun.

Museum in a swimming pool where the water still flows.

Where lovers tie birch branches into long-lived knots.

Unchanged for centuries, this medieval library keeps its books in chains.

A Dutch museum preserves the world's most diverse collection of vertical slices of soil.

Various sculptures are a rotating exhibit in this small town.

Thousands of miniature bronze sculptures have taken over this city square creating a unique art installation.

Super-heavy Nazi architectural experiment.

A collection of abandoned typographic signs from Berlin and beyond.

A remarkable cabinet of curiosities in an art space in the center of Berlin.

An elegant chandelier hangs over this ancient sewer chamber, now open for concerts and public tours.

This mine is home to the largest man-made hole in Europe.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

Op-art architecture designed for happiness.

The prototype for all Nazi concentration camps.