The entire Korean peninsula was a Japanese colony since 1910 till the end of World War II. Following the defeat of Japan in the World War II, Korean peninsula was divided along 38 degree parallel (latitude). The Soviet-led communist bloc was given the authority over North Korea while South Korea passed on to the capitalist western power group led by the US.
In June 1951, North Korea under Kim Sung-II invaded South Korea in a unification attempt. A coalition force of the NATO countries - mainly the American troops were in it - intervened from the southern side. But the North Korean army pushed them to what is called Pusan Perimeter. North Korea seized Seoul, the South Korean capital within three days of war.
The US-led troops launched a bold offensive to capture Seoul back from North Korea. While the odds were turning against North Korea, China sent its troops to bail out its ideological ally. Seoul again fell to the communist forces.
By August, the multinational forces of the capitalist bloc recaptured Seoul once again. The city had changed hands for the fourth and final time over two months of war.
North Korean leader Kim Jong-un and South Korea's President Moon Jae-in held talks in April earlier this year in the demilitarised zone to end mutual animosity the two Koreas have fostered for nearly seven decades.
The Korean War went on for two years from 1951 to 1953 with each side suffering some setbacks and making some gains on other fronts. The original boundary between North and South Koreas was altered a little over the period.
Diplomatic efforts were made and an armistice was reached in July 1953. Representatives from China, North Korea and UN-led United Nations forces signed the truce agreement after 158 rounds of talks. But South Korea's the then President Lyngman Rhee refused to sign the document. He was a votary of unification of Koreas under Seoul's leadership.
A demilitarised zone of about 250 km long and 2 km wide on either side of the border was created. Besides minor skirmishes, the divide line has remained peaceful given the scale of war-mongering propaganda from the respective sides in the last 65 years.
The current South Korean President Moon Jae-in was intent on signing on the dotted lines to end the war.
But, Trump and Kim apparently did not give him the chance to use his pen.