Paris: Cluny Museum

The Cluny Museum is a fantastic repository of medieval artifacts that was built on top of the ruins of a Roman bath from the 3rd century. It is most famous for a tapestry series called The Lady and the Unicorn, but my favorite pieces were the gold works and the stained glass. Stained glass (although common in Paris) never gets old to me. And to see it up close and be able to take in all the details is really special, since usually stained glass is placed up high in lofty cathedrals. A few other fun things to note: the original heads of the kings of Judea on the front of Notre Dame can be found here. During the French Revolution, the people mistakenly believed the carvings were the kings of France. So the poor kings of Judea were beheaded just like Louie XVI. The heads were eventually recovered, preserved here, and replaced on the Notre Dame by replicas. Also, be sure not to miss the "frigidarium," one of the rooms of the original Roman baths that has been subsumed into the museum. There's nothing quite like wandering through a museum only to find yourself in a room that itself is almost 2000 years old.