What are the most famous massacres?

the Texas chainsaw massacre and columbine and it would have been a massacre but at my school there were two kids plotting to kidnap, torcher, and brutally kill 2 to 5 people. they also planned to bring video cameras and become much like the killer jigsaw because they were "inspired" by him. the mom of one of them was listening on the other liine when they were plotting this and called the police. Another one which is much less interesting one is the mountain meadows massacre

I was looking for the same thing cause its interesting