U-boat "wolf packs" ravage Allied convoys early in the war, but ingenuity, new technology and a bit of luck help the Allies turn the tide by 1943.

In late 1942, America enters the war in North Africa, where the British have been battling the Germans and Italians for control of the Suez Canal.

Desperate for a victory in the East, Germany attacks toward Kursk in the summer of 1943 and triggers a monumental tank battle with the Soviet Union.

Hoping for a swift victory, Allied armies invade Italy in September 1943, but the fighting quickly grinds down to a bloody, months long campaign.

Paris suffers under German occupation throughout the war, until Resistance fighters within the city rise up to drive them out in August 1944.

In June 1944, a monumental battle between American and Japanese aircraft carriers in the Philippine Sea turns the tide in the Pacific.

In early 1945, US Marines invade Iwo Jima and face an appallingly bloody battle for control of the island, to the dismay of the public back home.

Angling for power in the postwar world, Stalin tricks the Allies — and his own generals — to ensure the Red Army wins the race to Berlin in April 1945.

US forces invade Okinawa in April 1945, and months of fighting and dreadful casualties persuade Truman to drop the bomb on Hiroshima and Nagasaki.