These films brought Chinese animation to the world stage at that time. The golden age ended with the outbreak of the Cultural Revolution in 1966, which dealt the animation film industry a hard blow, and limited the productivity of the studio. During the period of the Cultural Revolution, the whole studio was shut down by the Red Guards from 1965 to 1972. Almost all the animated films produced before were prohibited except "The Cock Crows at Midnight" (1964) by Yiou Lei, a puppet film about overthrowing evil landlords, and "Two Heroic Sisters of the Grasslands" (1964), directed by Qian Yunda and Tang Cheng, singing the praises of Mao Zedong and the Communist Party of China: "There area countless stars in the sky. But greater by far is the number of the commune's sheep. In the sky are pure white clouds. But whiter yet is the wool of the commune's sheep. Whiter yet is the wool of the commune's sheep. Our beloved Chairman Mao Dear Chairman Mao , under your sun the prairie prospers. Our beloved Communist Party, Dear Communist Party. The little shepherdesses grow under your leadership. The little shepherdesses grow under your leadership…" ["Two Heroic Sisters of the Grasslands" (1964)] Famous movies such as "Buffalo Boy and the Flute"(1963) and "Havoc in Heaven" (1961,1964) were banned because of the "ignorance of class struggle" and implication of overthrowing the government. Many of the leaders and artists of the previous productions of the studio were rounded up and forced into prisons or peasant villages to self-reflect on their anti-revolutionary action. In 1973, animators were gradually sent back to the studio, but most animations during this era were made for propaganda use in order to educate illiterate groups of the masses about contemporary political affairs, including "Support Vietnamese to Fight Against America", "Expose the Peace Negotiation Conspiracy of America", and "After School". In the same year, Wang Shuchen and Yan Dingxian made "The Little Balu" (1973), a story of a boy joined the liberation Red Army. The bold graphic style of characters and background corresponded to the style of prevailing propaganda posters around the country at the time. Not until the fall of the Gang of Four in 1976, did the studio finally recover under the stabilized political situation. Returning animators started to work on the projects that they had left for years. In 1992, one of the first Western companies to come in contact with the studio was Prrfect Animation in San Francisco, United States.