 To develop socialism, the Soviet Union underwent rapid industrialisation with pragmatic programs of social engineering that transplanted peasant populations to the cities, where they were educated and trained as industrial workers and then became the workforce of the new factories and industries.Likewise, the farmer populations worked the system of collective farms to grow food to feed the industrial workers in the industrialised cities.Since the mid-1930s, Marxism–Leninism has advocated an austere social-equality based upon asceticism, egalitarianism and self-sacrifice.