The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

This "floating railway" is one of the world's oldest monorail systems.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The real life town from the Pied Piper of Hamelin has a mechanical puppet show that retells the famous story many times a day.

Home to the world's oldest functioning orrery.

This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

Remarkably preserved body discovered in a peat bog.

This large sand dune in the Netherlands is home to wind-whipped trees with "floating" roots.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

A UFO-shaped event building originally intended to be a science museum showcasing the future.

A beautifully eclectic mix of architectural styles.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A moving memorial to the fallen and missing from WWI trenches.

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

This ghost town in Belgium will lose its street art when it ceases to exist.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

A visionary precursor to the Internet made of index cards.

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

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

It houses the remains of a 17th-century version of the Titanic.

Hundreds of Buddhas in a re-discovered Indonesian temple.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.