Gaoyou lake has been recorded as a "mirage" for many times in history, mostly in summer and autumn. On a sunny day after rain, streets and pedestrians suddenly appeared on the lake. Among the pedestrians, there are people who carry burdens to sell vegetables, people who buy vegetables with baskets, businessmen and guests, women with children in their arms, farmers working in the fields, and sometimes endless mountains emerge. These scenes are looming and illusory.