In the 1970's North Korea repeatedly threatened the South and dug many tunnels. At that time a joke was making the rounds that this time the North Koreans would definitely come by boat because last time only Pusan, at the southernmost tip, did not fall.
七○年代，北韓頻頻向南韓挑釁，還挖了許多地道，當時流行一則笑話，說是北韓軍隊這回一定搭船來，因為六二五韓戰只差最南端的釜山沒有攻下。