Photo of a (currently) dry, dusty cave south of the Atlas mountains. In the past, water was flowing down this large stalagmite formation. We date tiny pieces of stalagmite (~0.25g) to establish when the cave was wet in the past. Credit: Ben Lovett Analysis of Moroccan stalagmites reveals that the Sahara received increased rainfall between 8,700 and 4,300 years ago, supporting early herding societies. This rainfall, likely driven by tropical plumes and monsoon expansion, narrowed the desert, improved habitability, and facilitated human movement. Analysis of stalagmite samples from caves in southern Morocco has revealed new details about past rainfall patterns...