Chouara Tannery in Fes: The Traditional Leather Craftsmanship
To give you an idea, the process begins with the raw animal skins being soaked in a mixture of cow urine, pigeon poop, quicklime, salt and water. Sounds disgusting, but this tried and tested method has been used for over thousand years, so they must be doing something right.
The quicklime helps to remove the hair from the skins, while the acid in the pigeon poop softens the skins. They are kept in this massive vat, which is turned repeatedly by hand:
