Yes, Wadi Rum was once submerged under the sea during the Cambrian period, approximately 500 to 540 million years ago. Geologists have found extensive evidence of this aquatic history, including ancient marine fossils embedded within the sandstone layers and distinct sedimentary patterns formed by shallow sea currents. At that time, the entire region was part of the African continental plate and was covered by a warm, shallow ocean where early aquatic life flourished long before land plants evolved. Following this period, tectonic movements and the emergence of the Red Sea rift caused the land to uplift, and subsequent millions of years of water and wind erosion carved out the majestic red sandstone cliffs and deep sandy valleys we see today. The striking contrast between the dark granite basement and the lighter Cambrian sandstone provides a visual timeline of this transition from a vibrant underwater world to the arid, "otherworldly" desert landscape that now attracts travelers from all over the globe.