Also known as Dar el Ma (Water Palace) for the reservoir beneath, the granaries were one of Moulay Ismail's greatest achievements and are the first place any Meknessi will take you to give you an idea of the second Alaouite sultan's exaggeratedly grandiose vision. The Royal Granaries were designed to store grain as feed for the 12,000 horses in the royal stables -- not just for a few days or weeks but over a 20-year siege if necessary. Ismail and his engineers counted on three things to keep the granaries cool enough that the grain would never rot: thick walls (12 feet), suspended gardens (a cedar forest was planted on the roof), and an underground reservoir with water ducts under the floors. The room on the far right as you enter has a 30-foot well in its center and a towpath around it -- donkeys circulated constantly, activating the waterwheel in the well, which forced water through the ducts and maintained a stable temperature in the granaries. Out behind the granaries are the remains of the royal stables (the roofs were lost in the 1755 Lisbon earthquake). Some 1,200 purebreds, just one-tenth of Moulay Ismail's cavalry, were kept here. At a point just to the left of the door out to the stables, you can see the stunning symmetry of the stable's pillars from three different perspectives.