Last updated 2026-11-12 — Below a small waterfall over ten feet high in the river at the foot of Ruyuan Mountain lies a pool, which the ancients called "Heilongtan (Black Dragon Pool)." On the western rocky cliff of the pool is a spring. In summer and autumn, the spring water flows with a murmuring sound, cascading down from above and dropping into the pool, producing a sound like bells and chimes...