From Ocean to Desert: 5 Places That Were Once Under the Sea!

• Many large deserts today, including the Sahara, Arabian, Mojave, Kalahari, and Great Victoria, were once ocean floors.
• Evidence like marine fossils, salt layers, shells, and corals in rock strata confirms these areas were once water-filled.
• The Sahara Desert was submerged under the Tethys Sea 100 million years ago, with whale and shark fossils found in Wadi Al-Hitan.
• The Arabian Desert was a shallow sea connected to the Indian Ocean, now marked by saline flats and marine sedimentary rocks.
• The Mojave Desert (USA) and Great Victoria Desert (Australia) also show evidence of ancient seas, while the Kalahari Desert was a massive ancient lake.

Why It Matters: Earth's landscape constantly reshapes; many deserts were once oceans, evidenced by marine fossils and geology.