Among the Third World solidarity posters adorning the walls of the Valley Peace Center in Amherst, Massachusetts in the early 1970s was one particularly striking photo of a handsome, heroic Mozambican Frelimo guerilla. Above him the text read: Stop The Cabora Bassa Dam! I had no idea why we should stop it, but if the Frente de Libertação de Moçambique said so, that was good enough for me.