Best explored at dusk when the desert is at its most peaceful, the ancient city of Kysis may have lost its glory of old but the remains of its Roman Fortress, built out of unfired bricks and housing a temple dedicated to Isis and Osiris-Serapis, are extremely impressive. The site inspired delight among archaeologists when they unearthed the "Dush Treasure", a sumptuous set of jewels, and exhumed more than 500 remarkably well-preserved mummies from Roman times.