The Incredible Tanneries of Fes/Fez, Morocco If I had to pick just one highlight in Fes/Fez, it would have to be the incredible tanneries. No visit to Fes/Fez is complete without viewing from one of the many leather workshops that overlook the dye pots.The 11th century tanneries are the oldest in North Africa and this is where animals skins are treated and dyed before being sold and made into bags, jackets and belts. Each week, a different color dye is used and today's color happened to be red.