In temperate climates, "fairy rings" appear in grassy meadows and lawns, and these are caused by fungi, with some rings expanding for hundreds of years. But in the western part of Southern Africa, there are a different sort of "fairy circles," barren circles that are surrounded by long-lived perennial grasses. The Himba people, an ethnic group in northern Namibia, attribute them to original ancestor, Mukuru, or consider them "footprints of the gods," and scientists have been stumped for decades. Professor Norbert Jürgens, from the University of Hamburg, might have finally solved the riddle: a species of termites that are most active at night and don't build big, noticeable nests, have engineered the ecosystem by eating the roots of grasses that grow within the circle, keeping the soil moist for long periods of time. The discussion continues, as some scientists who have studied the phenomena aren't so sure about the theory.