A Belgian self-built tower inspired by the Bible and ancient civilizations.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.

This historical Netherlands fortress still bears the marks of its single siege.

Twisted buildings adorn the banks of the Rhine river.

What was once a bustling mining installation is now a bustling hub of contemporary art.

This unique bridge physically lifts a piece of the road into the air to let boats pass by.

An open-air sewer system that was covered piece-by-piece over 300 years.

Home to the world's oldest functioning orrery.

Take a walk in a recreation of ancient Rome.

An amusement park on the grounds of an unused nuclear power plant, with a swing ride inside the cooling tower.

Invisible bridge parts the waters, invoking biblical images and preserving the ominous feel of an ancient moat.