Guixu () is a location in Chinese mythology where all water, including the milky way, flow into a bottomless void. Even as water keeps flowing into it, the amount of water in it never changes. The term is a conglomeration of the characters for "return (to)" and "ruins". In interpretations of Guixu, the xu is sometimes conflated with its homophone, the Taoist concept of xu (), or an equilibrium state of emptiness or purity that one achieves through attunement with the Dao. Guixu in Liezi In the Taoist text Liezi, Guixu is located billions of li East of the Bohai Sea. There, all the water in the world flows. As the ancient Chinese considered the Milky Way to be a river of stars, they also believed all the stars in the Milky Way flowed into Guixu. . Floating atop Guixu were five sacred mountains - Penglai, Fanghu or Fangzhang, Yingzhou, Daiyu and Yuanjiao. The mountains were inhabited by xian and beasts who flew from one mountain to another. The tops of the mountains were said 9000 li wide and 70,000 li apart from each other. Its flat terraces were said to be made of gold, jade, and onyx. Eating the fruits of the trees atop the mountains granted immortality and everlasting youth. In order to make sure the mountains stayed stable for the xian, the ruler of the heavens ordered Yuqiang to command fifteen ao to stabilize the five mountains. The turtle is a legendary creature in Chinese mythology that is believed to have the power to cause earthquakes, as well as changes in the sea, mountains, and rivers. The fifteen ao were split into three groups who switched shifts once every 60,000 years. However, in the nearby Longbo Kingdom there lived giants whose strides were so large they could walk over to the mountains and fish six ao out. The Longbo giants burned the bones of the ao for oracle bone divination. As a result, the Daiyu and Yuanjiao mountains floated to the edge of the sea and sank. Billions of xian were forced to evacuate their homes. As punishment, the heavenly emperor cursed the Longbo Kingdom to shrink in area over time, forcing its people to also shrink in size to adapt.. Connection to Ganyuan Guixu is sometimes considered another name for Ganyuan (). Historian Guo Pu's annotations of mythology text Shanhaijing says Ganyuan was named so because