'If it is granted that the successful destruction of the target would warrant the possible expenditure of the entire force...' So wrote Major General Lewis Brereton, the US Ninth Air Force commander in the Middle East, as the planners contemplated the options of a high or low level attack on the oil refineries at Ploesti in Rumania. If this source of 40 per cent of Germany's oil could be eliminated, it would deal a vital bodyblow to the Third Reich's ability to wage war, and a surprise attack by heavy B-24 Liberators flying at tree-top height was considered the best method of achieving success. Three bomb groups from the Eighth Air Force based in Britain flew out to join two groups of the Ninth already in North Africa, the combined force of 179 aircraft destined to carry out the first massed low-level heavy bomber mission in history. The Ploesti Raid took place on Sunday, August 1, 1943 and, but for a navigational error which put the leading formation on a course away from the target, the operation might have resulted in the destruction of the seven chosen targets.However, by the time the mistake was realised, the defences were on the alert and over 20 Liberators were brought down in and around Ploesti. A further 35 aircraft were lost. Although the operation resulted in the award of five Medals of Honor - America's highest decoration for bravery - the cost was high: 308 airmen lost their lives and 208 were taken prisoner or interned. Out of the 1,753 men who are known to have set out on the mission, a total of 516 had failed to return.