This giant geoglyph of mysterious origins is now the site of neo-pagan rituals.

A fantastic castle rumored to be the birthplace of King Arthur.

One of the largest legal spray spots in Hamburg.

The highest peak in Wales is said to be the final resting place of a giant killed by King Arthur.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

Hiding the longest subterranean river known in the world.

A maze of crosses marks the jumbled divide between the Netherlands and Belgium.

This Dutch statue is a monument to the fictional shrew who brought doom to the city of Stavoren.

While most bridges allow roads to pass over water, this one allows water to pass over a road.

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

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

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

Wind power station for making famous Ketel One vodka.

The Rozenberg wind wall in South Holland makes for smooth sailing through the Calandbrug canal.

The struggle of a small Dutch island against the sea.

This giant wire frame man sculpture is crouched in contemplation.

The 20-mile causeway that separates the Netherlands from the sea.

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

This towering church is home to a world-famous organ and a treasure trove of medieval art.

This enormous storm barrier is one of the largest moving structures on Earth, with each arm taller than the Washington Monument.

This disused VLF radio station is no longer in service but the surrounding town still bears its name.

Home to the world's oldest functioning orrery.

“And the Lord said unto Johan, build for thee an ark for the end of the world is approaching.”

The ruins of a medieval castle that once belonged to one of the most powerful families in the Netherlands.