Perched on the edge of the Tabal Kawkaban (9,350 feet) is the ancient stone town of Kawkaban, which served as a mountain fortress for the residents of Shibam, living at the foot of the mountain, over 1,000 feet below.Inaccessible from most sides, the stout door of the town's only gate is still closed and locked each night. Several rainwater reservoirs enabled the inhabitants to survive long sieges. Until Yemen's civil war of the 1960's, Kwakaban had never been overrun.