Tacitus called the Garamantes ungovernable brigands, but clearly they were more than that. Deep in the Sahara Desert, from about 500 B.C. to 600 A.D., they cultivated the desert (see “Making the Desert Bloom”) and controlled trade routes from Egypt and the Mediterranean to tropical Africa. At the southwestern edge of their territory, they built a series of citadels, probably used as caravansaries and military outposts serving the trans-Saharan trade. The large Aghram Nadarif citadel, measuring 460 feet by 160 feet, was surrounded by a wall, built of stone blocks, and a number of watch towers—one of the well-preserved eastern towers is shown in the photo.