Wedged among the ancient buildings and serpentine passageways of Fez’s Old Medina in Morocco is a grid of stone wells, each filled with a colored liquid. This is Chouara, an 11th-century tannery that still operates as it did a thousand years ago. Pictured here, a man throws a camel hide ready for drying after soaking it in a mixture of cow urine, pigeon feces, quicklime, salt, and water. The leathers are then transformed into beautiful works of art available throughout the marketplace.