The discovery of fire, or, more precisely, the innovation of the controlled use of fire was, of necessity, one of the earliest of human discoveries. Fire's purposes are multiple, such as to add light and heat to the nights, to cook plants and animals, to clear forests for planting, to heat-treat stone for making stone tools, to keep predator animals away, to burn clay for ceramic objects. Undeniably, there are social purposes as well: as gathering places, as beacons for those away from camp, and as spaces for special activities.