A B-17 Flying Fortress (WE-J, serial number 41-2467) of the 305th Bomb Group. Image stamped on reverse: 'Associated Press.' [stamp]. Printed caption on reverse: 'REHEARSING RAID ON ENEMY TERRITORY. Hours of gruelling practice in the frigid sub-stratosphere over England is carried out by US Air Crews in Flying Fortresses before they are seasons to raid enemy territory. Their practice targets are often innocent midlands towns, but at the briefing they are told it is "Berlin"- for the purpose. Spitfires weaving above, below and around provide the "defence" for the target and give the gunners some useful hints in what to do and what not to do when attacked. Associated Press Photo Shows: A Flying Fortress high over England speeding on a practice raid.'