May 20, 2017
•1949 -- Kim Yak-su and Lee Mun-won, then lawmakers in South Korea's first National Assembly, are arrested for arguing for the withdrawal of foreign troops from the country and negotiations for the reunification of the two Koreas. As a result of their assertions, the two lawmakers were accused of being communist sympathizers.
•1954 -- The country's third parliamentary election is held.
•1962 -- The South Korean government revives a nationwide curfew. The curfew was originally imposed in 1945 and finally abolished in 1982.
•1980 -- The Supreme Court confirms the death sentence for Kim Jae-gyu, former head of the Korean Central Intelligence Agency, who assassinated then-President Park Chung-hee in October 1979. He was executed in May 1980.
•1986 -- Lee Dong-su, a student activist at Seoul National University, burns himself to death at the school's student center, calling for "the eradication of U.S. imperialism" and punishment of then-President Chun Doo-hwan, who Lee called a fascist.
•2003 -- Lee Keun-young, former head of the Financial Supervisory Commission, is arrested on charges of arranging illegal loans to Hyundai affiliates in 2000 in connection with a scandal involving payoffs to North Korea ahead of the first-ever inter-Korean summit.
•2010 -- A probe led by an international team of investigators concludes that a North Korean torpedo sank the Cheonan warship on March 26 near the tense inter-Korean border in the Yellow Sea, killing 46 sailors.