The article suggests that knowing the history of the Crips and the Bloods may help identify, investigate, and understand gang behaviors. In the mid-1950's, African-American neighborhood youth groups were developing in South Central Los Angeles. These were active social organizations involved with house parties, car clubs, school dances, and getting together at particular roller skating locations. Rivalries developed among groups, and smaller neighborhoods started to band together for protection. Gang activity flourished and declined during various periods in the late 1950's and 1960's. In 1968 the first groups appeared that later became known as the Crips. To protect themselves from the Crips, the other Los Angeles-based African-American street gangs banded together. This group became known as the Blood gangs, completing the polarization of West Coast African-American street gangs, who are no longer social organizations, but are involved in violent and illegal activities. The Crips and the Bloods are rivals to this day.