Saudi deserts once had rivers, lakes and grasslands: Study

New studies reveal Saudi Arabia’s deserts were once rich landscapes with rivers, lakes and vast grasslands that supported plants, animals and early humans. The Rub’ al-Khali, now an ocean of sand, was once a huge lake, while hippos, crocodiles and other water-dependent species thrived during wetter climatic phases. When the climate shifted, the waters vanished and sands reclaimed the land.