After the war, Korea remained divided into two countries. In North Korea, the communist dictator Kim Il Sung established collective farms, developed heavy industry, and built up the country's military power. At Kim's death in 1994, his son Kim Jong Il ascended to power. Under Kim Jong Il's rule, Communist North Korea developed nuclear weapons. Although the country is well armed, it had serious economic problems. It continues to struggle with shortages of energy and food. On the other hand, South Korea prospered, thanks to massive aid from the United States.