This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A subterranean shelter remains intact under a busy Paris railway station.

The history of radiation is on safe display at the foot of a radiation science laboratory.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

This hidden collection of everyday objects illustrates life within communist Poland.

The traditional Polish croissant, folded 81 times into the shape of a horseshoe, is a legally protected cultural treat.