The Butterfly Spring is located at the foot of the Yundong Peak, one of the peaks of Cangshan Mountain, in Dali of Yunnan Province. The spring water is as clear as a mirror, with tens of thousands of butterflies gathering here from all around every year, dancing all over the sky. Some of these butterflies are as big as one's palm; others are as small as a copper coin. One after another, strings of butterflies hang down from big silk trees to the surface of water, dazzling to the eye.

Legend has it that the Butterfly Spring was originally called bottomless pool, where lived a father and a daughter named Wen Gu, who was intelligent and beautiful. After Wen Gu grew up, she engaged herself to a hunter named Xia Lang. But before long, she was seized by a landlord. Xia Lang risked his life to rescue her and ran with her. The two lovers committed suicide by jumping into the spring to escape the chasing government troops. Flashes of lightning struck at once, followed by crashes of thunder, violent storm and gusty rain. When the sun shone again after rain, two big beautiful butterflies flew out of the pool, followed by numerous little ones. That day was April 15 on Chinese lunar calendar. From then on, countless butterflies gather here on this day, telling of that touching love story. This famous phenomenon is known as the meeting of butterflies.