Present day Long Cheng (Long Tieng). From the early 60s until 1975 this was the main operating base for the Central Intelligence Agency air assets (Air America) during their covert war in Laos. Never appearing on any map or public document yet once the busiest military airport in the world, Long Tieng was described for many years as 'The Most Secret Place on Earth'
Headquarters to over 25,000 CIA led Hmong guerilla fighters, Thai regulars and mercenaries in their fight against NVA and Pathet Lao forces. The CIA called the effort 'the largest paramilitary operations ever undertaken by the CIA'.