In August 1976, North Korean soldiers attacked a group of US and South Korean men trimming a poplar tree in the heavily-guarded zone that divides the two Koreas.
Two US officers were bludgeoned to death with axes and clubs.
After three days of deliberations going all the way up to the White House, the US decided to respond with a colossal show of force.
Hundreds of men – backed by helicopters, B52 bombers and an aircraft carrier task force – were mobilised to cut back the poplar.
Six of the men who took part told the BBC about their part in the most dramatic gardening job in history.
A small neutral camp called the Joint Security Area (JSA) lies on the border between North and South Korea, in the area known as the Demilitarised Zone (DMZ). Both were created under the terms of the armistice signed in 1953 which ended the Korean War.
The JSA – also called Panmunjom, or the Truce Village – is where negotiations between both sides take place. Most recently, it was where US President Donald Trump stepped into North Korea, becoming the first US leader to do so.
But in 1976, guards and soldiers from both sides could wander all around the small zone. North Koreans, South Koreans and US guards would mingle together.
Bill Ferguson was just 18 years old in August 1976. He…