East of the Bohai Sea. I don't know how many millions of miles away there is a big ravine, but it is actually a bottomless valley with no bottom below it, so it is called Guixu. The water of eight rivers and nine fields, the flow of sweat from heaven, are poured into it without any increase or decrease. . . . . . Among them are five mountains, one is called Daiyu, the second is called Yuanqiao, the third is called Fanghu, the fourth is called Yingzhou, and the fifth is called Penglai. The height of the mountain is 30,000 miles, and the flat top is 9,000 miles. The mountains are 70,000 miles apart... But the roots of the five mountains are not connected. They always go up and down with the tides and cannot stand still for a while.
——"Liezi·Tang Wen"