See: Historical Amnesia: Worst U.S. Massacre? by Carla Blank (May 2, 2007).
My Lai
Cork
um claymore as worst anime and pretty face as wrost manga
me
My Lai Massacre
The My Lai massacre profoundly impacted the US public by fueling anti-war sentiment and increasing opposition to the Vietnam War, leading to widespread protests and demands for accountability. Within the US Army, it raised concerns about military conduct and ethics, prompting reforms in training and engagement rules. The Vietnamese government viewed the massacre as emblematic of American brutality, intensifying resentment and resistance against foreign intervention. For the US government, it resulted in a loss of credibility both domestically and internationally, prompting inquiries and a reckoning regarding military operations in Vietnam.
It really depends on how you mean worst.
I deleted your World of Warcraft account.
Of course there was in 1961
The British view it as hardly a massacre which influenced the forming of an outspoken Anti British public opinion.
us
The Massacre at Mystic changed the US because it was the vision of what would happen to Native Americans for many years to come.