Describe the first sit-in and its impact on the civil rights movement.

The first was the Woolworth's sit-in at the lunch counter in Greensboro, MS--this sit-in showed the power of a simple non-violent protest. 

Sit-ins challenged the Jim Crow segregation laws at their core. Blacks sitting where they were not allowed by the laws forced a reaction from whites. Either they must use force against non-violence or change their policies.