Butterfly Spring is at the foot of Yunlong Peak in Cangshan Mountains, 30 kilometers north of the ancient city of Dali. The clean spring water squeezes its way out of sand and pebbles at the bottom of a 50-square-meter pond. The pond is circled by marble rails. Above the rail, there are three marble rocks. On them are three Chinese characters reading "Butterfly Spring" in famous modern writer Guo Moruo's calligraphy. Around the pond are tall trees. In summer, these trees blossom and attract flocks of butter flies, and hence are called "Butterfly Trees." In the middle of the fourth lunar month, the scene is particularly attractive, and the Butterfly Spring Festival is held on the 15th day of the fourth lunar month each year Butterfly Spring is a famous tourist attraction.