Monday, June 6th is a national holiday in Korea known as Memorial Day. It is a sombre day, held to commemorate and pay respect to millions of lives lost during the Korean War.
The Korean War itself began around five years after the end of World War II. During World War II, Korea was occupied by Japan. At the end of the war, two countries staked a claim on Korea; Soviet Russia took control in the north and the US took control in the south. A borderline of sorts was at the 38th parallel. On June 25, 1950 North Korean troops invaded south of that parallel, beginning the war.
South Korean troops were aided by the United Nations, who flew in thousands of soldiers, including many from the UK and US. They were able to push the North Korean troops out of Seoul and back up toward the 38th parallel, and by 1951 armistice talks had begun. In 1953, the country was divided into North and South, with a two-mile demilitarized zone (the DMZ) inbetween. No peace treaty has every been signed in Korea, so officially the two states are still at war. This is the reason why South Korean men have mandatory military service even today.
On Memorial Day itself, a siren sounds at 10am. Officials and the general public will lay flowers at the graves of soldiers, much like remembrance day in the UK. South Korean flags are often raised as part of the ceremony, or displayed on people’s front doors. The Seoul National Cemetery is the final resting place of many soldiers, and a major ceremony is held here for people to pay their respects.
Further reading
A BBC History article written by a British man who served during the Korean War
A guide to the DMZ from the Korea Tourism Organization
A blogger shares some photos and directions to the Seoul National Cemetery