By the beginning of the Central Europe Campaign, Allied victory in Europe was inevitable. Having gambled his future ability to defend Germany on the Ardennes offensive and lost, Hitler had no real strength left to stop the powerful Allied armies. Yet Hitler forced the Allies to fight, often bitterly, for final victory. Even when the hopelessness of the German situation became obvious to his most loyal subordinates, Hitler refused to admit defeat. Only when Soviet artillery was falling around his Berlin headquarters bunker did he begin to perceive the final outcome.[37] The crossing of the Rhine, the encirclement and reduction of the Ruhr, and the sweep to the Elbe-Mulde line and the Alps all established the final campaign on the Western Front as a showcase for Allied superiority in maneuver warfare. Drawing on the experience gained during the drive from Normandy and the advance to the Rhine, the western Allies demonstrated in central Europe their capability of absorbing the lessons of the past. By attaching mechanized infantry units to armored divisions, they created a hybrid of strength and mobility which served them well in the pursuit warfare through Germany. Key to the effort were the logistical support that kept these forces fueled and the determination to maintain the forward momentum at all costs. With these mobile forces making great thrusts to isolate pockets of German troops which were mopped up by additional infantry following close behind the Allies rapidly eroded Hitler's remaining ability to resist.[38] For their part, captured German soldiers often claimed to be most impressed not by American armor or infantry but by the artillery. They frequently remarked upon its accuracy, the swiftness with which it acquired targets, and especially the prodigality with which artillery ammunition was expended.[39] In retrospect, very few questionable decisions were made concerning the execution of the campaign. Perhaps atton could have made his initial Rhine crossing north of Mainz and avoided the losses incurred crossing the Main. Also, the airborne operation in support of the 21st British Army Group's Rhine crossing was probably not worth the risk. But these decisions were made in good faith and had little bearing on the ultimate outcome of the campaign. On the whole, Allied plans were excellent as demonstrated by the rapidity with which their objectives were met. In the end, just as the Red Army's destruction of the Wehrmacht in the east established the Soviet Union's position as a postwar superpower, so the U.S. Army's leading role in the final conquest of Germany, not only in providing manpower and materiel, but also in terms of strategy and tactics, presaged the important new position the United States would occupy in the postwar world. The Invasion of Normandy was the invasion and establishment of Allied forces in Normandy, France, during Operation Overlord in 1944 during World War II. It was the largest amphibious operation ever to take place. Allied land forces that saw combat in Normandy on 6 June came from Canada, the Free French Forces, the United Kingdom, and the United States. In the weeks following the invasion, Polish forces also participated, as well as contingents from Belgium, Czechoslovakia, Greece, and the Netherlands.[4] Most of the above countries also provided air and naval support, as did the Royal Australian Air Force, the Royal New Zealand Air Force,[nb 1] and the Royal Norwegian Navy.[1] The Normandy invasion began with overnight parachute and glider landings, massive air attacks and naval bombardments. In the early morning, amphibious landings on five beaches codenamed Juno, Gold, Omaha, Utah, and Sword began and during the evening the remaining elements of the parachute divisions landed. The "D-Day" forces deployed from bases along the south coast of England, the most important of these being Portsmouth.