I need acts of violence that created major social change.?

We are doing a project of the 20th century and for every twenty year span, we are to write a paper about a topic. I chose violence.



Does anyone know acts of violence and how they changed the social climate in the United States?I need acts of violence that created major social change.?
mafia/mob (creating a slew of social laws)



race related crime (we implimented hate crime laws)



entitlement crimes in economic downturns (this seems constant, and the same situation occurs each ';crisis'; most recently seen during the race riots in CA, and during Katrina



kidnappings took a spike in the eighties, changing the way we alert people, to help find the victims, this also changed social behaviors the most (in my opinion) because when this crime again took a downturn (it is rare for a stranger to kidnap a child now) parents still sequestered their children (and still do)



and ritual abuse took a spike between the seventies and the nineties (cults, etc) {I am not sure if this caused a social change, as it appears that we went back to the Constitution on this one {militia outside the US government}



other crimes like murder seem to grow with the population, but stay comparatively the same



gang violence has been spiking since the eighties (not mafia, children, and adult gangs) (social changes in laws, and actual human behavior, from creating new laws and working on prevention, but also human social behavior has been affected, from acceptance and extreme fear, to moving out of affected areas)



women have been murdering for a long time on massive levels, but the defined examples are just now hitting the forefront of the media (research munchausen, munchausen by proxy) but so far this has not really changed social behavior that I have seen, as women are still seen as victims, rather than criminals...



for example:



Mary Ann Cotton was not considered a serial killer, but she murdered between 15 and 21 family members with poison



Beverly Allitt murdered four children, and tried to kill 9 more before she was caught, she was also not called a serial killer, and was defined under munchausen by proxyI need acts of violence that created major social change.?
Hate crimes ....um.....k.k.k. attacks.... um..... James Byrd ...(in 1990's he was a black man and his death was really tragic) even president clinton contacted the family ..and it changed a town and the nation a bit .. ....and... Columbine High school.... in 99.. the shooting
you could talk about spectacle lynchings (white men hanging black men) that happend in the early 1920s.



White men would hang black men in the center of town and entire city blocks would come out to see the hanging. It caused hundreds of race riots and lead to sundown-towns (google James Lowen and Sundown towns) and later segregation across the USA.



http://www.withoutsanctuary.org/main.html