With the need for more serious training, the Army has established a formal school called the Jungle Operations Training Center in 1953. Since then, the school became home to thousands of trainees not just because of its exceptional training but because of its unique nature. The school’s setup is already challenging with its tree roots and vines, over 100 poisonous or injurious varieties of flora, poisonous snakes, and bugs, and so much more. The school closed down in 1999 but luckily, it was reopened in Hawaii in 2014.
Source: https://www.wearethemighty.com/military-life/jungle-warfare-school-was-called-a-green-hell/
