A long-closed church turned into a saintly skate park.

A nuclear reactor created for Eisenhower's "Atoms for Peace" campaign is now used for research at a Dutch university.

This Dutch windmill has its roots in an American invention.

From afar it looks like someone's hat blew into the water, but closer inspection reveals a giant floating sculpture.

It's forbidden to dig within this ancient Roman fort hidden beneath a playground.

The tallest mountain in mainland Netherlands isn't actually very tall.

Portraits of musicians line Oude Binnenweg, the jazziest street in the city.

A striking memorial to the Jews of Leiden who were murdered during World War II is scattered throughout the city.

Albert Einstein would often sit in this chair during visits to the observatory to discuss science with Willem de Sitter.

Watch the local Netherlands birds from inside this giant eco-egg.

This bell tower is the only one of its kind in the Netherlands and was a symbol of prestige.

For over 100 years the most important physicists in the world have autographed this university wall.

One of the great math minds of the 17th century is underfoot in this 900 year old Dutch church.

This bronze statue of Martin Luther King was placed in the park without permission.

This giant radio telescope would be a rusting ruin if it hadn't become such a beloved relic.

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

A rare double mill nestled along the banks of the Aa river.

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.

An enormous Polaroid picture adds an artistic flair to Rotterdam.

This artificial ring island was built to hold cubic tons of polluted dirt.

Four giant movable street lights decorate this modern Rotterdam square.

An early 19th-century English style garden hidden in the Rotterdam cityscape.

This gigantic monument hidden in the woods was built to thank the Dutch for sheltering Belgian refugees during World War I.

A nearly 25-foot concrete sculpture of Sylvette, Picasso's muse.