On the left bank of the Dujiangyan water conservancy project, there is a majestic building called Qin Yulou. On March 21, 1958, Chairman Mao Zedong visited Dujiangyan and carefully watched Dujiangyan at this location, so here is also known as "happiness platform", "observation platform". This is the best location to overlook the Dujiangyan panoramic view.