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

The highest point in Belgium is a staircase to nowhere.

The "stairway to heaven" lookout tower was built to resist weather, arson, and the laws of physics.

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

In an area where the remnants of WWI are discovered on a regular basis this preserved frontline trench may be the most amazing.

A rare example of World War I trenches from the British front.

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

The portrait of a man from Japan who sent weekly letters to a Dutch hotel he never visited.

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

The last of Amsterdam's original sea level markers remaining in place.

Repurposed space and ultra-modern construction collide to create this geometric wooden spectacle.

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

An overgrown and largely forgotten cemetery lies hidden within the outskirts of Amsterdam.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

A museum dedicated to a Cold War era sausage.

A museum in the building where Nazi Germany signed its surrender tells the story of World War II from the Soviet perspective.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

The final resting place of many of Germany's most famous communists.

One of downtown Berlin's last reminders of its Communist past.

Berlin's oldest surviving academic architecture hosted decades of animal dissections.

This conical hill was built as a testing ground for an engineer known as the Glider King.

Super-heavy Nazi architectural experiment.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.