Excellent post from Steve on the forum “Some 5.5 million years ago the force of Africa colliding with Europe, closed the straits of Gibraltar, sealing off the Med, which then evaporated over 2000 years. The straits were then breached by the Atlantic and the basin filled up again over 100 years. This happened many times and resulted in massive salt accumulations. The Nile and Rhone created deep canyons as they cut down to the deep desert basin than had once been the Med” Read complete post Also watch this video.