A design by master architect Alvar Aalto in a small village in the Apennines near Bologna.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

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

Unchanged for centuries, this medieval library keeps its books in chains.

A grassy pyramid named after a French battle.

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