La Llorona is a Latin/American urban legend about a woman who drowns her children in a river because her husband left her for a younger woman. Realizing what she had done she drowned herself in the river as well.
The legend says that she now wanders the Earth looking for her children. Parents would use this story to scare their children into behaving because they say that she would kidnap wandering children who resemble her own. Universal has used this legend for a few haunted houses and a scarezone.