What is Moroccan leather tanning and its history?

No craft hits travellers as hard — literally — as the tanneries. The most famous is the Chouara tannery in Fes, which has operated in essentially the same way since the medieval city was built; you stand on a terrace above a honeycomb of stone vats filled with white liquid and rainbow dyes, while men work waist-deep among them. It is one of the oldest continuously functioning tanneries in the world, and watching it is like stepping straight into the Middle Ages.

The process is brutal and ingenious. Raw hides — cow, sheep, goat, camel — are first soaked in the white vats, a caustic mix of lime and, traditionally, pigeon droppings, whose ammonia softens the leather and strips the hair. Workers then knead and tread the hides by foot, before moving them to the coloured vats. The dyes are largely natural: poppy and madder for red, saffron and turmeric for yellow, indigo for blue, henna for brown, mint and pomegranate for green. The result is the supple, jewel-toned leather Morocco is famous for.

The smell is, I will be honest, overwhelming — guides hand you a sprig of fresh mint to hold under your nose, and you will need it. But I never let clients reduce the tanneries to a smell and a photo. This is dangerous, gruelling, low-paid work performed by hand in conditions that have barely changed in a thousand years, and the leather that emerges — turned into babouche slippers, bags, poufs and jackets — supports whole families and an entire quarter of the medina.

Historically, Moroccan leather (the fine goatskin Europeans called "morocco leather") was a prized export, used to bind books and make luxury goods across Europe for centuries. When I bring people here I try to give them that long view: that the bag they might buy downstairs is the end of a chain reaching back through guild masters, medieval trade routes and an unbroken craft tradition. Stand on the terrace, breathe through the mint, and watch history at work.