Selma, Alabama was a site of major organizing
for voting rights.  On March 7, 1965, 600
marchers set off from Selma to Montgomery to protest police brutality and demand voting rights.  As the marchers tried to cross Selma's Edmund Pettus Bridge, they were attacked by state troopers, chased and  clubbed to the ground. 
This day became known as "Bloody Sunday."