What is "pingliang"

Pingliang is a prefecture-level city in eastern Gansu province, China, bordering Shaanxi province to the south and east and the Ningxia Hui Autonomous Region to the north. Pingliang is well known for the nearby Kongtong Mountains, which are sacred to Taoism and location of the mythical meeting place of the Yellow Emperor and Guangchengzi, an immortal.