According to a CIA report in 1971, Mae Salong was then one of the largest heroin refineries in south-east Asia. Only in the late 1980s, after Khun Sa's army was finally routed and pushed over the border into Myanmar by the Thai military, was the Thai government able to make any headway in taming the region – part of which involved crop substitution plans and giving the area a new name. "Santikhiri" meaning "hill of peace" was introduced by the Thai government in an effort to disassociate the area from its former image as an established opium zone. King Bhumibol Adulyadej and other members of the royal family made regular visits as a sign of their support for the old soldiers who had fought against their own country for Thailand.