Wandering through the Medina in Fez, you see craftsmen of all sorts at work, their workshops often open right onto the narrow alleyways. The leather tanneries are slightly less accessible; you’ll smell them long before you see them. The tannery works can only be seen from upper floors of the leather shops that surround them.
It’s best to go in the morning when the dying is done. Looking down from a 2nd or 3rd floor terrace, you’ll see rows of earthen vats, some filled with cow urine, lime and pigeon poop, some with all natural dyes made from plants and minerals – reds, blues, greens, black, browns – and workers thigh deep in the vats, working the submerged hides with their feet. (Yellow dyes are made with saffron and, because of their relative expense, are applied by hand.) You’ll see goat, sheep, cow and camel hides stacked around waiting to be dyed or hanging on racks and walls drying in the sun. You’ll smell the cow urine, which, together with lime, breaks down any fat and hair remaining on the hides. You’ll smell pigeon poop, which is used as natural softening agent. It’s really stinky, I won’t lie, but you will be armed with a sprig of fresh mint, which will take the edge off. The entire process is done today as it has been for 1,000 years.
On the way out, you will be encouraged by the shop keepers to buy something but it’s not required. If you’re so inclined, the leather is very high quality and, since you’re right at the source, it’s a good value. If you’re a good bargainer, you should get away paying half or even a third the sticker price.