The Mara Salvatrucha gang originated in Los Angeles, set up in the 1980s by Salvadoran immigrants in the city's Pico-Union neighborhood who immigrated to the United States after the Central American civil wars of the 1980s.
Definition. The Sierra Club is the oldest grassroots environmental organization in the United States. The organization was founded in 1872 by a San Francisco group of professors, businessmen, and other professionals led by John Muir (Cohen 1985, 10).
Beginning Our Second Hundred Years Of Activism for the Environment. On November 1, 1911, 75 Sierra Club members gathered in downtown Los Angeles to sign a petition calling for the creation of a Southern California Section, the first local chapter in the history of the organization that John Muir founded in San Francisco in 1892.