The 1975 Beirut bus massacre (Arabic: مجزرة بوسطة عين الرمانة ,مجزرة عين الرمانة), also known as the Ain el-Rammaneh incident and the "Black Sunday", was the collective name given to a short series of armed clashes involving Phalangist and Palestinian elements in the streets of central Beirut, which is commonly presented as the spark that set off the Lebanese Civil War in the mid-1970s.