Battle of Hamburger Hill the steeply-sloped hill against well entrenched troops. Attacks were repeatedly repelled by the PAVN defenses. Bad weather also hindered operations. Nevertheless, the Airborne troops took the hill through direct assault, causing extensive casualties to the PAVN forces. The battle took place on Dong Ap Bia (Ap Bia Mountain, ) in the rugged, jungle-shrouded mountains of South Vietnam, from the Laotian border. Rising from the floor of the western A Sầu Valley, Ap Bia Mountain is a solitary massif, unconnected to the ridges of the surrounding Annamite range. It dominates the northern valley, towering some above sea level. Snaking down from
Rudolf Hamburger route which involved a combination of buses and trains, but both Patra and Hamburger believed that this was unacceptably dangerous because of the war. The alternative route, approximately three times as long, involved travelling by ship to Hong Kong, from where it would be possible to take a flight to Chongqing, Chiang Kai-shek's wartime capital between 1937 and 1946. Hamburger intended then to follow a land route from Chongqing Xi'an. Although he had a large amount of luggage to take, Patra still insisted that Hamburger should travel with a radio transmitter-receiver so that they might stay in touch. The device