From June 10th to the 29th in 1987, millions of people in South Korea took to the streets to protest, demanding a direct presidential election and ending Chun Doo-hwan's military dictatorship.

On December 12, 1979, Chun Doo-hwan, then-leader of the Security Command, launched the Coup d'état of December Twelfth. In doing so, he seized ultimate military power. After suppressing the Gwangju Uprising the following year, Chun was elected President for a seven-year term. South Korea had entered the period of the Fifth Republic.

In April 1987, in an attempt to keep himself in power for the foreseeable future, Chun issued a statement refusing to amend the constitution. This triggered popular protests. In 1987, the authorities' treatment of three college students sparked public outrage: At the beginning of 1987, Jong-chul, a member of the pro-democracy movement, was tortured to death by the police; Kwon In-sook was subjected to sex torture by the police; and in June, Lee Han-yeol was killed by a tear gas cannister fired by riot police. The growing public outrage culminated in the nationwide June Democracy Movement.

Under the tidal wave of public opinion, presidential candidate Roh Tae-woo (who had been nominated by Chun Doo-hwan's ruling party), had to surrender. On June 29th, 1987, Roh issued the June 29 Declaration. This included eight concessions, including direct presidential elections and protection of freedom of speech. The Declaration slightly alleviated the turmoil in the country. On October 27th of the same year, South Korea's National Assembly passed the Constitution of the Sixth Republic, thus establishing South Korea's Sixth (and current) Republic. On December 16th, 1987, Roh Tae-woo won the presidential election. In doing so, he became the first truly democratically elected president of the Republic of Korea, officially launching the period of South Korea's democratization.

References: [台灣國際研究季刊("Taiwan International Studies Quarterly"")(Chinese)] (http://www.tisanet.org/quarterly/7-2-7.pdf); [關鍵評論 ("The News Lens")(Chinese)] (https://www.thenewslens.com/article/159568)