An easy siq to explore is the narrow fissure that cuts into Jebel Khazali. You can explore on foot for about 150m, far enough to appreciate the cool shade and to see inscriptions made by the ancients who used the siq for the same purpose. Look out for drawings of ostriches, pairs of feet and a woman giving birth. You need ropes and a guide to penetrate further and 4WD transport to reach the siq.
