South of Ba Sing Se, the cliffs, one white the other red, stand facing each other with a wide ravine between them. Early Earth Kingdom natives noticed that the ground of the ravine was charred and black and legend holds that the cliffs were created in an ancient battle between Earthbenders and Firebenders, the conflict being so awesome that the very ground they fought on soaked up their power and animosity. The cliffs currently are mined for "spark rocks," small, craggy stones used by Earth Kingdom citizens to start fires.