The second element of the complex was the Heri as-Swani or Heri es-Souani, a vast area of silos which were adjoined to the southwest side of the House of the Ten Norias.[1][2][3] (The name is sometimes also applied to both structures together.[4]) This structure measured 182 by 104 meters and was divided by 22 rows of thick arches between which ran vaulted corridors.[5] The building is often mistakenly referred to as the "stables" or "royal stables" of Moulay Isma'il, but it was in fact an enormous grain storage warehouse which could stockpile supplies to withstand a long siege.[8][6] Grain was delivered to the building by mules who climbed onto a roof terrace and dropped the grain directly into holes pierced above each vaulted corridor, though one interior corridor also remained free for interior circulation. Today, the vaulted roofs have collapsed and disappeared, leaving only the endless rows of arches which are nonetheless considered one of the most impressive sights in the city.[8]