La llorona, or The Weeping Woman, is the story of a poor Mexican woman who married a rich Spaniard. After they had children, the Spaniard started losing interest in his wife and was embarrassed to be married to a woman without prestige.
In a rage, the woman took all of her children to the river and drowned them thinking that would appease the Spaniard, but she was instantly hit with regret. She started screaming "Mis hijos, mis hijos," which means "My children, my children."
People say that to this day, La Llorona wanders near river banks looking for her children. If La Llorona finds any children near the river alone, she lures them to the water, and drowns them.