Members of the 101st Airborne land on Hill 937, aka "Hamburger Hill." Many LZ's (landing zones) like this one were under constant fire from PAVN positions. (Je Me Souviens) On this day in 1969, American UH-1 "Huey" helicopters began landing in the A Sầu Valley, a remote, densely-jungled region of Vietnam close to the Laotian…