varied along what would come to be seen as important dimensions: Time: Did the killings occur more or less simultaneously, or did they extend over several days, months, or years? Place: Did the killings occur in a single location, or in a variety of places? Method: How were the victims killed?" In the late decades of the Twentieth Century and early years of the 2000s, the most popular classifications moved to include method, time and place. While such classifications may assist in gaining human meaning, as human-selected categories, they can also carry significant meaning and reflect a particular point of view of the commentator who assigned the descriptor. See also Crimes against humanity Gun violence List of rampage killers Mass destruction Mass grave School shooting Suicide attack Terrorism War crime List of wars and anthropogenic disasters by death toll References External links What makes a Mass Killer? Mass Murder: A Small Person's Way to Immortality Mass shootings interactive map Online Encyclopedia of Mass Violence The real causes of mass murder by James Alan Fox. Boston.com, January 16, 2011. (murder of 4 or more people) Murder