Fes is one of the four so-called "imperial cities" (the others are Marrakech, Meknes and Rabat). It is separated into three parts, Fes el Bali (the old, walled city), Fes-Jdid (new Fes, home of the Mellah), and the Ville Nouvelle (the French-created, newest section of Fes). The Medina of Fes el Bali, the largest of the two medinas of Fes, is believed to be the largest contiguous car-free urban area in the world. Fes el Bali is classified as a UNESCO World Heritage Site. The University of Al-Karaouine was founded in 859 A.D. and is the oldest continuous operating university in the world.
FYI - It is Fes, not Fez (fez is a felt hat)