Bare circles of earth ringed with tall grass are found all over Africa. They have been a mystery with all kinds of stories told about them. Now a partial explanation has been found. Walter Tschinkel has been studying the phenomenon since 2005. At first he thought they were caused by termites which poisoned and killed off the grass. He realized his mistake when he analyzed satellite images - the circles were alive! The circles would disappear then appear somewhere else. However, for the most part circles remain in one place for up to 75 years. The average life was 41 years. Rain tends to be the main factor leading to formation of a new circle. Tschinkel has not discovered the real cause. If fertile earth is put inside a circle grass still will not grow. Something is going on in a chemical or "living" sense. Locals do not want the mystery solved. They make a living out of them. For a fee tourists "adopt" a circle, then keep up-to-date by viewing it on Go