The Sahara Desert was once filled with rivers, huge lakes, and hippos. Scientists explain why it turns green every 20,000 years | World News
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July 22, 2026
For most people, the Sahara Desert is the ultimate symbol of endless sand, sweltering heat, and one of the harshest environments on Earth. Geology, however, tells a very different story. Beneath the dunes are the remains of ancient rivers, vast lakes and…