An immense desert–semi-desert corridor from Mauritania to Chad. Sparse rainfall, nomadic ranges, and long caravan routes define movement and settlement. The Sahara’s emptiness isolates societies, while the Sahel’s grasslands provide narrow east–west bands of habitation. Civilization here emerges along trade lines, oasis networks, and the control of trans-Saharan exchange. Geography produces mobile cultures, warrior confederations, and commercial nodes rather than dense agrarian states.
