The Cultural Revolution damaged China's economy and traditional culture, with an estimated death toll ranging from hundreds of thousands to 20 million. Beginning with the Red August of Beijing, massacres took place across mainland China, including the Guangxi Massacre, in which massive cannibalism also occurred; the Inner Mongolia incident; the Guangdong Massacre; the Yunnan Massacres; and the Hunan Massacres. Red Guards destroyed historical relics and artifacts, as well as ransacking cultural and religious sites. The 1975 Banqiao Dam failure, one of the world's greatest technological catastrophes, also occurred during the Cultural Revolution. Meanwhile, tens of millions of people were persecuted: senior officials, most notably Chinese president Liu Shaoqi, along with Deng Xiaoping, Peng Dehuai, and He Long, were purged or exiled; millions were accused of being members of the Five Black Categories, suffering public humiliation, imprisonment, torture, hard labor, seizure of property, and sometimes execution or harassment into suicide; intellectuals were considered the "Stinking Old Ninth" and were widely persecuted—notable scholars and scientists such as Lao She, Fu Lei, Yao Tongbin, and Zhao Jiuzhang were killed or committed suicide. Schools and universities were closed with the college entrance exams cancelled. Over 10 million urban intellectual youths were sent to the countryside in the Down to the Countryside Movement.