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).
siÂ·erâ²ran adj. Word History: In English, the word sierra is probably best known for the names of certain mountain ranges, such as the Sierra Nevada (in Spanish, the snowy sierra) of Spain, the similarly named Sierra Nevada of Eastern California, and the Sierra Madre (the mother sierra) of Mexico.