In 1950 the U.S government sent military advisers to train tribal police along the border of Thailand. Among them was Harold Mason Young, son of American missionaries, who had been born in Burma. Young started helping injured animals, and his collection started getting visitors. The Chiang Mai provincial government set aside 24 acres (9.7 ha) at the base of Suthep Mountain, and the facility was opened to the public in 1957.[1][3]