resulting in the two countries remaining technically at war. Approximately 3 million people died in the Korean War, with a higher proportional civilian death toll than World War II or the Vietnam War, making it one of the deadliest conflicts of the Cold War era. In addition, virtually all of Korea's major cities were destroyed by the war. Post-Korean War (1960–1990) In 1960, a student uprising (the "April 19 Revolution") led to the resignation of the autocratic then-President Syngman Rhee. This was followed by 13 months of political instability as South Korea was led by a weak and ineffectual government. This instability was broken by the 16 May 1961 coup led by General Park Chung-hee. As president, Park oversaw a period of rapid export-led economic growth enforced by political repression. Park was heavily criticized as a ruthless military dictator, who in 1972 extended his rule by creating a new constitution, which gave the president sweeping (almost dictatorial) powers and permitted him to run for an unlimited number of six-year terms. The Korean economy developed significantly during Park's tenure. The government developed the nationwide expressway system, the Seoul subway system, and laid the foundation for economic development during his 17-year tenure, which ended with his assassination in 1979. The years after Park's assassination were marked again by political turmoil, as the previously suppressed opposition leaders all campaigned to run for president in the sudden political void. In 1979, General Chun Doo-hwan led the coup d'état of December Twelfth. Following the coup d'état, Chun Doo-hwan planned to rise to power through several measures. On 17 May, Chun Doo-hwan forced the Cabinet to expand martial law to the whole nation, which had previously not applied to the island of Jejudo. The expanded martial law closed universities, banned political activities, and further curtailed the press. Chun's assumption of the presidency through the events of 17 May triggered nationwide protests demanding democracy; these protests were particularly focused in the city of Gwangju, to which Chun sent special forces to violently suppress the Gwangju Democratization Movement. Chun subsequently created the National Defense Emergency Policy Committee and took the presidency according to his political plan. Chun and his government held South Korea under a despotic rule until 1987, when a Seoul National University student, Park Jong-chul, was tortured to death. On , the Catholic Priests Association for Justice revealed the incident, igniting the June Democratic Struggle across