The discovery and utilization of fire, a simple energy source with many profound uses, was a turning point in the technological evolution of humankind.^[28] The exact date of its discovery is not known; evidence of burnt animal bones at the Cradle of Humankind suggests that the domestication of fire occurred before 1,000,000 BC;^[29] scholarly consensus indicates that Homo erectus had controlled fire by between 500,000 BC and 400,000 BC.^[30][31] Fire, fueled with wood and charcoal, allowed early humans to cook their food to increase its digestibility, improving its nutrient value and broadening the number of foods that could be eaten.^[32]