The event that marked the beginning of the murdering of civiliam by terrorists in 1972 was that Palestinians terrorists kidnapped and murdered eleven Israeli athletes at the Munich Olympics.
Terrorism in the 1970s took place against a backdrop of the final years of the Vietnam War, a conflict in which more than 58,000 Americans died, and the Cold War, which sustained the possibility of nuclear annihilation.
After Palestinian terrorists claimed the life of 11 Israeli athletes and coaches hostage at the Munich Olympics in 1972, the entire world seemed to be watching the tragic event unfold. It resulted in the massacre of all of the hostages and the death of most of the terrorists.