A thousand and more drawings are engrave on the stone faces on both sides of a 600-meter-long stretch of a ravine in Helan Pass o the eastern slope of the Helan Mountain some 50 kilometers from downtown Yinchuan. Most of these engravings are in the images of human heads, and the others are renditions of cattle, horses, goats, donkeys, deer, birds, wolves and other animals, as well as the sun, the moon, stars, and human limbs. Some of the pictures depict scenes of hunting and sacrificial rituals. These works of art form a veritable treasure-house of ethnic art, furnishing precious materials for the study of the history, culture, economy and religious beliefs of the northern nomads of ancient times.