The Palais des Papes is a historical palace in Avignon, southern France, one of the largest and most important medieval Gothic buildings in Europe. One time fortress and palace, the papal residence was the seat of Western Christianity during the 14th century. The Palais is actually made up of two buildings: the old Palais of Benedict XII which sits on the rock of Doms, and the new Palais of Clement VI, the most extravagant of the Avignon popes. Wiki.
The Pont Saint-Benezet,also known as the Pont d'Avignon,spans the Rhone.Before the heavy flooding of the Rhône prevailed,the bridge had 22 arches,connecting the left bank of Avignon with Barthelasse island where there were many taverns in the nineteenth century.This is probably where they danced as the famous nursery rhyme says.