Science meets wall art to highlight the beauty of famous mathematical equations.

The Netherlands' first car tunnel has an unusually rectangular shape.

Lumps of significant stone from around the world surround a flaming monument for peace.

This charming pup is meant to celebrate the youth and stubbornness of the city's students.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

A giant floating rubber duck-bunny painted with a different design every year.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

This former hydraulic laboratory is now a woodland dotted with old engineering models.

Atop this former dutch railway office sits an interstellar work of art.

It's believed this golden brick is part of the legendary lost Aztec treasure.

This stunning and ethereal mural symbolizes the beauty, unity, and diversity of humankind.

The unique collection often goes unnoticed by visitors focused only on the archaeological objects.

Part bookstore, part café, and part forest.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

A tribute to the 20th-century ball that cast a spotlight on Mexico’s LGBTQ community.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

This crumbling Art Deco movie palace in Mexico City has been abandoned for two decades.

A fabulously bizarre surrealist sculpture by the late artist Leonora Carrington.