On the morning of 21 March 1943, Colonel Rudolf Christoph Baron von Gersdorff stood waiting inside the Zeughaus, Berlin’s old armory, with two British mines in the pockets of his uniform tunic. The fuses were not yet armed. He intended to ignite them the moment Adolf Hitler came near, and to die with the Führer in the blast. Hitler was already on his way across the city from the Reich Chancellery, driven in his armored Mercedes limousine, to attend the annual Heldengedenktag—the Day of Commemoration of Heroes.

Every senior figure of the Nazi state would be present, along with the assembled leadership of the armed forces. Gersdorff, a staff officer from Army Group Center on the Eastern Front, was part of a conspiracy of army officers who had decided that killing Hitler was the only way to change the course of the war. He had volunteered for the task, and he knew that if the mines worked as promised, he had perhaps ten minutes to live. The solemn ceremony at the Zeughaus almost never took place.

The day of commemoration itself was a recent invention. In 1934, the new National Socialist government set out to overhaul the way Germany remembered its war dead. Like most countries, Germany reserved one day a year as a day of remembrance, originally created—like Britain’s Remembrance Day and America’s Veterans Day—to honor the immense number of fallen from the First World War. The Weimar Republic had established it in 1922 as Volkstrauertag, People’s Mourning Day, observed with a reserved ceremony inside the Reichstag, the German parliament building in Berlin.

But the Nazis grasped the power of visuals, of pomp and display. Joseph Goebbels, the Reich propaganda minister, was charged by Hitler with turning the day of mourning into something more celebratory and nationalistic. In 1934 he created Heldengedenktag, the Day of Commemoration of Heroes. The focus shifted from remembering the dead to hero worship, and the center of the day was Hitler himself.

By 1943, the hero’s commemoration day looked less like a celebration and more like a funeral service for Nazi Germany. It would mark Hitler’s last appearance at the annual event. He had begun to withdraw from public life as his physical infirmities worsened, and as defeat followed defeat on the battlefields. The 1943 ceremony was particularly gloomy and melancholy because Germany had just suffered its greatest military defeat of the war so far: Stalingrad.

The entire German Sixth Army had been battered, surrounded, and forced to surrender following a terribly mismanaged campaign in the Soviet Union, a campaign for which Hitler bore ultimate responsibility. More than 300,000 German and Axis troops had been killed, wounded, or captured in the city. The balance on the Eastern Front had swung decisively to the Red Army, and Germany would now be almost permanently on the defensive in the east. Stalingrad was a true turning point of the Second World War.

Hitler’s appearance in public so soon after the disaster was meant to steady the nation. He would attempt to reassure the German people that all would be well, that ultimate victory in the east would still come. But for some in the army, killing Hitler had now become the only way to change the course of the war, and the Heldengedenktag parade offered the best opportunity to do it. As Hitler arrived in front of the Zeughaus, he was greeted by senior representatives of the four branches of the armed forces: Grand Admiral Karl Dönitz of the navy, Field Marshal Wilhelm Keitel of the army, Field Marshal Erhard Milch of the Luftwaffe, and Reichsführer-SS Heinrich Himmler.

Moving inside, the first movement of Bruckner’s Seventh Symphony filled the interior of the old building. At one o’clock, Hitler ascended the podium to speak. His address was short. He claimed that the army had successfully stabilized the Eastern Front following the disaster at Stalingrad, and his speech contained the familiar criticisms of Germany’s enemies, along with the usual resolution to be victorious.

He ended by praising Germany’s fallen—as much a funeral address for the Sixth Army and Fourth Panzer Army as an address to all Germany’s fallen in two world wars. When the speech ended, Hitler moved to another part of the Zeughaus, where a display of captured Soviet weapons had been set up. Among the officers waiting to interpret the exhibits for the Führer was Gersdorff. The baron was not just any staff officer; he was part of the conspiracy of army officers plotting to kill Hitler.

In his uniform tunic pockets he carried the two small British clam mines. As Hitler approached him, Gersdorff activated the ten-minute fuses. He was determined to stay close to the Führer and blow himself up along with Hitler in the explosion. An extraordinary photograph from that moment shows Gersdorff standing close to Hitler and other Nazi leaders, his bombs already armed.

But then something happened that Gersdorff had not counted on. Hitler, looking extremely disinterested and unsettled, barely glanced at the exhibits. The plan had assumed the Führer would wander through the display for about thirty minutes. Instead, after barely two minutes, he abruptly left.

Had he sensed something was wrong? Gersdorff excused himself and dashed to a lavatory stall, managing to defuse both mines with little time to spare. His plot was not detected by Hitler’s security force. The next part of the event now got underway.

Leaving the Zeughaus, Hitler was met by the Berlin garrison commandant, Major General von Haase—who, incidentally, was also in on the plot to kill him. Hitler then reviewed the assembled troops outside the adjacent Neue Wache, a Prussian-built former royal guard house that had been repurposed as a memorial to the fallen of the First World War. Following the troop review, four Knights Cross–holding officers, one from each branch of the armed forces, jointly carried a large wreath inside the Neue Wache. Hitler ceremoniously helped to lay the wreath at the memorial court.

After the wreath laying, Hitler met a hundred carefully selected veterans of both world wars—wounded or disabled men—spending a few minutes speaking to individuals and listening to their stories. The final part of the ceremony involved a march-past by the honor guards of the four services, parading the colors and standards of the various units, with Hitler taking the salute. Then it was over. The attempt to assassinate Hitler had failed, not because of any security measure, but because Hitler’s own restless impatience had taken him out of the kill zone after only two minutes.

Gersdorff had come closer to succeeding than almost any other would-be assassin in the war, yet the opportunity passed. Following the 1943 Heldengedenktag, Hitler rarely spoke in public again. His last major public address occurred in November 1943, when he spoke to 10,000 officer cadets at Breslau. In 1944, he spoke publicly only twice: on the first of July, giving a funeral address for the famed mountain troop general Eduard Dietl, and on the fourth of July, a private address to 200 leaders of German industry at the Platterhof hotel, adjacent to his private house on the Obersalzberg.

The Day of Commemoration of Heroes would go on without him, and the man who had once been its center would never again stand before the nation on the day he had recreated in his own image.