How an ancient society in the Sahara Desert rose and fell with groundwater

With its low quantities of rain and soaring high temperatures, the Sahara Desert is often regarded as one of the most extreme and least habitable environments on Earth. While the Sahara was periodically much greener in the distant past, an ancient society living in a climate very similar to today's found a way to harvest water in the seemingly dry Sahara—thriving until the water ran out.