MS-13 (Mara Salvatrucha also known as simply MS or Mara) is an international criminal gang that originated in El Salvador. In the 1980’s, the gang spread to Los Angeles, California, many parts of the continental United States, Canada, Mexico, and Central America, and is today active in urban and suburban areas. Ross Kemp travels to El Salvador to report on what has become one of the most notorious and violent criminal gangs in North and Central America.