55 years after sending a hit squad on a deadly raid in Seoul, North Korea has found new ways to threaten South Korea

In January 1968, North Korean commandos slipped across the border into South Korea. They were headed to Seoul on a secret and daring mission to kill South Korea's president. A

half-century later, Pyongyang is finding new ways to threaten South Korea's leaders. Just before midnight on January 17, 1968, 31 North Korean special forces soldiers cut

through a wire fence along the demilitarized zone and infiltrated South Korea without detection. The commandos, part of a specially trained force called Unit 124, had one

objective: kill South Korean President Park Chung-hee. Their plan was to covertly make their way to the presidential residence, a 62-acre compound known as the Blue House in

Seoul's Jongno district. Once there, they would bypass the outer checkpoints and then conduct an all-out assault on the main building. A little more than 300 yards from

their target, however, everything fell apart.At a boiling point Tensions on the Korean Peninsula were approaching a boiling point by January 1968. While the US and South

Korean militaries were increasingly focused on the Vietnam War, North Korean dictator Kim Il Sung seemed dead-set on reminding the world that the Korean War had not officially

ended. Violent incidents along the DMZ increased from 42 in 1966 to 360 in 1967 — including at least 100 firefights that killed 63 US and South Korean servicemen and wounded

190 more. (That year, the US military classified Korea as a hostile fire zone, making US troops there eligible for combat medals.)