Tattoos that read: 'MS 13,' 'MS' or '13? represent the Mara Salvatrucha gang from El Salvador. The MS 13 tattoo is often inkedon its member'sfaces, necks, or hands. The Mara Salvatrucha was started in the Los Angeles by El Salvadoran immigrants. There are several MS-13 chapters all over the United States, with a total of over 70,000 members. The Mara Salvatrucha is known as one of the most brutal gangs in America.