Black Lives Matter Founded by Alicia Garza, Patrisse Cullors, and Opal Tometi

In response to George Zimmerman's acquittal, Alicia Garza wrote a social media post that Patrisse Cullors amplified with the hashtag #BlackLivesMatter. Opal Tometi helped build the online infrastructure. The three women are credited as co-founders of Black Lives Matter, which grew into one of the most significant civil rights movements of the 21st century.