The April 3 Incident
An uprising on Jeju Island on April 3 (4 - 3), 1948 led to a military response by the national government that devastated the island and created a large number of casualties, including many women and children, over the next months and years. The exact number of deaths has never been precisely determined, but estimates place it between 15,000 and 30,000—10% or more of the island's population at the time. The tragedy is one of the deadliest in the modern history of Korea, second only to the Korean War. A detailed report on the incident, prepared by the government-appointed National Committee for the Investigation of the Truth about the Jeju 4 - 3 Incident (under the chairmanship of the Prime Minister of Korea, Goh Kun) was released in 2003. In October of that year, and again on April 3 of 2006, the then-president of Korea, Roh Moo-hyun, offered a formal apology to the people of Jeju Island for what he referred to as 'the illegal exercise of state power' against them.
More information can be found in the following websites and reports:
69th Memorial Ceremony (2017)
Buddhist monks praying for the victims (2017)
Victims' family and relatives performing a memorial service (2017)
Missing victims' gravestones (2017)
Jeju Governer Won, Heeryong (2017)
A crowd of people at the ceremony (2017)
A group of politicians paying their respect to the victims ( Prime Minister Whang, the president candidates Cheolsu Ahn and Sangjeong Sim attended, 2017)
A replicate of the site where victims were collectively killed and buried. Many victims were unidentified, and only a handful of people were identified by DNA tests.
An old couple leaving the venue after the ceremony (2017)