After the founding of the People's Republic of China in 1949, Mao Tsetung established a system of labor camps for systematic repression, known as Laogai, an abbreviation for "reform through labor". In such camps, forced labor and physical and mental torture were used to bring about a so-called mental reform, re-education in the spirit of the Chinese Communist Party. Millions of Chinese were affected. Many were executed. In hundreds of camps, the Party took advantage of the prisoners' free labor to build the economy. Self-criticism and denunciation were often the only way to escape martyrdom. Successive waves of purges culminated in the Cultural Revolution, which saw massive human rights abuses, political assassinations, massacres, and exiles in remote parts of the country.