North Korea has announced its leader Kim Jong-il died on Saturday at the age of 69. He reportedly suffered a heart attack while traveling on a train. Known as the Dear Leader, Kim took over North Korea in 1994 when his father Kim Il-sung died. The two men are the only leaders North Korea has known since its founding in 1948. Kim Jong-il’s youngest son, Kim Jung-un, is expected become North Korea’s new leader. South Korea put its military on alert soon after the news of Kim Jong-il’s death was announced earlier this year. Technically the two countries are still at war. Under Kim Jong-il’s leadership North Korea became a nuclear state. In 2003, it quit the nuclear Non-Proliferation Treaty. Three years later, it tested its first nuclear device. While North Korea was becoming a nuclear state, an estimated one million North Koreans died during a famine in the 1990s.