Beginning in the late 1950s, Chicago based street gangs developed into a hierarchical-style gang structure in the juvenile facilities and jails of Chicago and expanded throughout Cook County, Illinois. As with Los Angeles based gangs, many of the early leaders of Chicago based gangs met a bad end, either ending up being imprisoned or dead (murdered, executed, or dead of natural causes at an early age). Gang wars killed literally thousands in the rapid expansion of gangs across the United States. Chicago based gangs have a multistate following and often absorb local gangs when they arrive in an area.