"Famous for Killing Each Other" refers to the notorious rivalries and conflicts between historical figures or groups that have led to significant violence or death. This phrase often highlights the dramatic and tragic outcomes of these confrontations, which can include battles, duels, or political assassinations. Examples include the rivalry between Alexander Hamilton and Aaron Burr, which culminated in a fatal duel, and the ongoing conflicts between various mafia families in the United States. These events are often remembered for their impact on history and culture, illustrating the extremes of human conflict and ambition.