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).
Still others might point to May 28, 1892 as the day when the U.S. environmental movement began. That is the date of the first meeting of the Sierra Club, which was founded by noted preservationist John Muir and is generally acknowledged as the first environmental group in the United States.