They were caused when four African American college students when into a cafe and were refused service. They then decides to stay sitting there until they got served. The other guests, who were white, were not happy with what the college students were doing.
Protests began outside the cafe.
Their goal in this was to show that they deserve equal treatment. They were also trying to demonstrate protesting was possible in a non-violent way. Eventually the news about the sit-ins spread and people were joining in all across the country. One huge this is the Martin Luther King Jr. publically spoke out to show is support of the sit-ins. This greatly helped to spread the word about what was going on and what needed to be done.
Martin Luther King Jr. speaking out in support of sit-ins
They had a lot of obstacles when doing this. This was a very time consuming process. They were also extremely disrespected by whites in the cafe at the time of the sit-in. They had food and other things thrown at them while they were sitting. Still they managed to remain silent and let it not affect them. They had the end goal in mind and were determined to stay focused.