Every so often, a new dance craze sweeps the nation.

The first one I remember seeing in person was the Macarena, which showed up out of nowhere and conquered my elementary-school dances swiftly and without mercy. My classmates and I were powerless against it. Even if you hated it, you had no choice but to join in. Today, things are basically the same: If you have kids, odds are one of them has done the Dab or the Floss since you started reading this.

But none of our modern moves are anything compared to the original dance mania — a literal compulsion that swept Europe, off and on, throughout the Middle Ages. For reasons nobody has ever been able to fully explain, large groups of people were suddenly taken with the desire to start dancing, and nothing could compel them to stop. People danced for so long... Read More