Enormous thick (23 feet) arched walls of the imperial granaries of the Sultan Moulay Ismail, are part of the kasbah or Imperial City of Meknes which were used as storage area for the grain supply to feed the citizens of Meknes and also for hay and grain storage for the 12,000 horsed stabled in the buildings adjacent. There are series of cisterns 130 feet beneath the storage areas that were fed by conduits leading from the reservoir just nearby which kept the floors cool, thus preserving the grain using this refrigeration process.