For decades it was as chilling a symbol of the Cold War as the Berlin Wall: the DMZ, Korea's laughably mis-named "demilitarised zone", stretching 155 miles across the peninsula along the 38th parallel, prickly with landmines and tank traps, the buffer zone that kept the huge armies of the North and South apart.
It marks the point where the Korean War began and ended, and yesterday the ghosts of that conflict swarmed back as Pyongyang announced that it no longer accepted the armistice agreement that ended the war on 27 June 1953.
They call it "the Forgotten War" because it was overshadowed by the Second World War and the Vietnam War, but none of the tens of thousands of British soldiers who slogged through the bitter cold of the peninsula's winter ever forgot it. More than 1,000 British soldiers died in the first proxy war between the Soviet Union – and later China – and the West.
At the end of the Second World War, the Soviet Union and the United States agreed to split Korea, Japan's former colonial possession, in two, along the 38th parallel.
Client regimes sprung up on both sides but neither regime accepted as permanent a division of the peninsula which was brutally artificial. Both made the unification of Korea their overriding political goal. The problem of course was that both sides wanted to impose their own system of government.
After years of violent border incidents, the war was tripped when tank regiments of the People's Republic poured south across the border on 25 June 1950. They came close to a clean sweep of the south before American forces finally halted them.
The Korean peninsula had been divided into a variety of independent states through the centuries, but it had never been sliced along the 38th parallel, a division which made no cultural, political or economic sense.
General Douglas Macarthur vowed to end the war with nuclear weapons, one reason why obtaining their own nuclear deterrent has been an obsession of the North's regime ever since.
After at least 600,000 soldiers had been killed and most of the peninsula's towns and cities destroyed, the war ended in a stalemate. The bitter hostility of the antagonists prevented them signing a peace deal – and now, even the half measure that silenced the guns has been tossed away.