Grains, beads and bangles unearthed from dig sites in Banda, Ghana, tell of a time when droughts did not bring famine. (Above) Archaeologists Amanda Logan and Osei Kofi dig into the floor of a house from the 1500s.
Courtesy of Ann Stahl/Northwestern University
A man harvests fruits of the Jatropha tree in Taabo, Ivory Coast. Jatropha, which is grown in many parts of the world, has fallen from favor as a diesel fuel substitute.
Kambou Sia/AFP/Getty Images