1943: The Battle of Kursk begins. It features the largest tank engagement in history. In purely military terms, it’s the most decisive battle of the European war. After Kursk, the defeat of Nazi Germany is certain.

Following their catastrophic defeat at Stalingrad five months earlier, the Germans lacked the strength to attack along the entire Eastern Front. The high command chose to focus on a salient near Kursk in Russia, near the Ukraine. There was an opportunity there to encircle and destroy a dozen Soviet armies. Following the elimination of that pocket, the Germans planned to strike...