Gangs have existed in the US since the 19th century and are defined by a system of rules and codes of behavior. They serve as substitute families for socially excluded individuals and provide a sense of empowerment. The two largest gangs, the Bloods and the Crips, were both founded in Los Angeles in the 1970s and have since spread nationwide engaging in violent criminal activities like drug dealing. Youth are drawn to gangs due to factors like absent role models, lack of economic opportunities, and a desire for belonging. According to a 1998 survey, there are over 23,000 youth gangs in the US with over 600,000 members across all 50 states.