by Sam Kean
In the spring of 1945, lilacs were scarce. Several villages around Haigerloch had been reduced to piles of stones, and dust from the rubble blew through the streets like Wild West ghost towns. The landscape seemed almost too quiet, in fact, and Lightning-A rolled into Haigerloch warily, spooked at the lack of resistance.
They located Heisenberg’s cave across the street from a few Bavarian-style homes with white walls and wooden shutters. It was a natural cave, with a jagged entrance roughly eight feet high. The cathedral atop the cliff had once stored its sacramental wine there, and in taking it over, Heisenberg and his assistants had code-named it the Speleological Research Institute. Pash’s crew dubbed it the “atom cellar.” The huge metal door covering the entrance was padlocked, so Pash hunted down the burgher with the keys and ordered him to open it. When he protested, Pash turned to his lieutenant: “Shoot the lock off. If he gets in the way, shoot him.” The keymaster was far more accommodating after that.
The cave stretched twenty-five yards deep into the limestone, its walls cool and damp. The candles that Pash and his sidekicks held aloft could barely penetrate the gloom, and they stepped forward cautiously, wary of booby traps. After a few yards they came to a huge pit in the floor, ten feet across, with a thick metal lid and an aluminum cylinder embedded inside. Above the pit, anchored to the low ceiling, was an overhead crane that drew power from a diesel generator in the Bierstube (pub) across the street. Wires for hanging uranium cubes lay nearby, and pipes and electrical cables snaked all around. It was the sanctum sanctorum, the Nazi nuclear reactor. On a blackboard to the side, someone had written a cryptic message in German: “Let rest be holy to mankind. Only crazy people are in a hurry.”
To their disappointment, Alsos found no uranium or heavy water in the cave; the Germans had apparently removed everything. But Pash was determined to deal the Nazi nuclear project a mortal blow. He put the whole town on lockdown, forcing everyone indoors. Then, after hauling out some valuable-looking equipment, he ordered his men to pack the cave with dynamite. He planned to bring down the whole cliff and caboodle above it, including the church, burying the atom cellar under thousands of tons of rock.
At the last minute, however, according to town lore, the local priest came scampering down a set of stairs carved into the cliff and begged Pash to spare the cathedral. Pash had orders to the contrary, but as the son of a bishop, he couldn’t deny a man of the cloth. So Alsos set off a much smaller charge, one that simply collapsed the roof of the cave. It was still enough to destroy the last lingering remnants of the Nazi atomic bomb project.
With the atom cellar buried, the hunt for the Uranium Club members began in earnest. Werner Heisenberg had already fled the area, reportedly to his family’s cabin in the Bavarian Alps. Other choice targets remained, however. Alsos found Otto Hahn working quietly in a nearby village, his briefcase already packed. Hahn detested the war—his son Hanno, Lise Meitner’s godson, had lost his arm on the Eastern Front fighting against Russia—and when an Alsos soldier entered his office, Hahn looked up and said in English, “I have been expecting you.” He went along quietly. Carl von Weizsäcker showed a little more attitude. Although relieved that the Americans and not the Russians had picked him up, he nevertheless looked down his nose at his captors as uncivilized apes. (To be fair, it couldn’t have helped his mood that the Alsos team, upon taking him into custody, had looted his wine cellar.)
In interrogating them, Pash and Goudsmit asked Weizsäcker and Hahn three things. Where’s the uranium from the atom cellar? Where’s the heavy water? And where are your technical reports? Just like at Strasbourg, Weizsäcker answered that he’d burned the papers—a disappointing but unsurprising answer. As for the three thousand pounds of heavy water, the Germans had siphoned it into oil drums, which they hid in a grist mill three miles distant. It was quickly recovered. Similarly, the Germans had buried two tons of uranium in a field atop a nearby hill. Liberating this took some work. Fearing booby traps, Pash forced a group of German prisoners to dig it up. And because the uranium had been cut into several hundred two-inch cubes, the Alsos team had to transfer it to waiting trucks by passing the cubes hand to hand down the hill, bucket brigade–style. A few scientists, including Goudsmit, pocketed one as a souvenir.
After securing the uranium and heavy water, Pash thought it prudent to scoot before the French caught on to his pilfering. His jeeps were headed out of town, in fact, when Weizsäcker spoke up and confessed something. He’d been listening to their questions over the past few days and had determined that Alsos wasn’t what he’d feared—a trophy brigade out for loot. (His wine notwithstanding.) They were “intelligent people,” he decided, people he could “talk sense” with. He therefore admitted that he hadn’t burned the German technical reports after all. He’d hidden them.
The jeeps screeched to a halt. Where? That was the rub. To ensure their safety, he’d sealed the papers in a drum and buried them where no one would ever look: in a latrine, beneath several years’ accumulation of human waste.
Perhaps Weizsäcker didn’t believe they’d actually go after the drum, but if so, he badly underestimated Alsos. Goudsmit dispatched two soldiers—each wielding a long pole with a hook—to go fishing for it. As a joke, Goudsmit declined to tell them what they had in store, only that it was a “very important top-secret assignment.” Both expressed gratitude that he’d singled them out for this honor. When they found out about the cesspool, they were awfully sore with him, but they got their revenge soon enough. After returning to the Alsos base they dumped the filth-streaked drum beneath the window of Goudsmit’s room. There was no need to alert him that they’d found their target—he could smell that for himself. After hosing the drum down, Goudsmit pried the lid off and discovered virtually the entire archive of the Nazi atomic bomb project. Boris Pash sent a cable to Washington announcing that “Alsos has hit the jackpot.”
The only sour note to Operation Big was that Werner Heisenberg had eluded capture. Alsos nevertheless managed to find his office before evacuating the region. It was located in an old woolen mill a few miles away. Few documents remained when Pash broke in, certainly nothing of value. But one item there remained burned into his memory forever. In the middle of the desk, in a place of pride, sat a framed photograph of Heisenberg and Goudsmit. They’d taken it together in Michigan in 1939, and for whatever reason Heisenberg had wanted it with him when he moved his lab south. Perhaps it reminded him of the last peaceful time in his life—before the war, before nuclear bombs, before all the trouble began.
Sorry to say, though, trouble had not stopped stalking Werner Heisenberg.
CHAPTER 56
The Lonely Organist
In January 1945, a few weeks after returning home from his lecture in Switzerland, Werner Heisenberg found himself in trouble with the Gestapo again. It turned out that an informant had infiltrated the dinner party in Zurich and had overheard him making “defeatist” remarks. Heisenberg instantly recalled the heavy-browed “Swiss physics student” who’d followed him to his hotel—clearly a Nazi agent. Who the real informant was, no one knows, but it took Heisenberg’s superiors every ounce of persuasion they had to spare him.
The month only went downhill from there. After losing the Battle of the Bulge, Germany revoked the military exemptions of most scientists, and Heisenberg was duly drafted into the Volkssturm—the People’s Militia, organized for a suicidal last defense of the Reich. He had to waste every Sunday training with them now instead of doing science. Not that his science was going much better. He’d recently moved his lab to the atom cellar in Haigerloch, where he planned to build his biggest Uranium Machine yet—one he hoped would go critical. He simply needed a few hundred gallons of heavy water, currently stored in Berlin, shipped south to Haigerloch.
But on February 1, the administrative head of the atomic bomb project, who was escorting the heavy water, called to tell Heisenberg that he’d made an impromptu decision: he was diverting the entire stock to—it was outrage
ous!—Kurt Diebner, who was working in a schoolhouse basement in a different town. From an impartial perspective, the decision made sense. However pathetic, Diebner had proved himself a dynamic nuclear scientist, and if anyone could throw together a working reactor at this stage, it was he. Heisenberg, though, wouldn’t stand for it. That was his heavy water; it was a matter of scientific honor. So on February 5, Heisenberg and Weizsäcker set out to take the D2O back, making a dash north that might have turned even Boris Pash’s hair white.
The duo started before dawn on bicycles, then hopped onto a train. When the track ahead of them got obliterated in an air strike, they arranged for a car to cover the remaining distance. But another air raid swept in while they were waiting, and they spent the next few hours huddled in a cellar listening to a cello sonata on the radio, with the bombs above adding an unwelcome bass line. Then things got really hairy. When they finally hit the road again, they discovered that cars were irresistible targets for gunners in planes. (Germany had zero air defense left, so the Allies could strafe at will.) Every time a plane appeared overhead, the two physicists and their driver had to screech to a stop and leap into the weeds alongside the road to keep from being blown to bits. It was long after dark when Heisenberg finally reached his boss. The heavy water probably still should have gone to Diebner, but the boss could hardly deny his star scientist after all he’d been through that day. Heisenberg returned triumphant with the canisters, his scientific honor restored.
He spent the next two months setting up the final Uranium Machine in the atom cellar. They were productive months, but lonely; to pass the time between experiments, he’d ascend to the cathedral on the cliff and play Bach fugues on the organ. Finally, in late March, the machine was ready. The business end of it looked like a Calder mobile—664 uranium cubes dangling from wires, eight or nine per strand. These were lowered into an aluminum vat in the floor filled with heavy water. To start things cooking, someone would shove a neutron source into a shaft leading into the center of the vat. The setup was dangerous—like dropping a grenade through the chimney of a gunpowder plant—but Heisenberg’s crew didn’t have time to set up safety shields. All they had was a lump of cadmium to cram into the chimney if things got out of hand.
In the end the experiment proved both a triumph and a dead end. Heisenberg’s crew managed to produce a neutron multiplication factor of 670 percent—a huge leap toward a self-sustaining chain reaction. Not even Diebner had approached such numbers. (No one in the world had, as far as Heisenberg knew.) Still, without more heavy water or uranium, he simply couldn’t goose any more neutrons out of the setup and achieve criticality. He and his team did keep tinkering—they had nothing better to do. But for all intents and purposes, this was the last gasp of the Nazi Manhattan Project.
By mid-April, the residents of Haigerloch could hear enemy tanks firing in the distance. Even this fairy-tale town, it seemed, was not exempt from the ravages of modern war. Heisenberg soon announced plans to evacuate and dismantle the Uranium Machine. He and Weizsäcker then hid the cubes in the field and the heavy water in the mill and the documents in the latrine.
Heisenberg was finally ready to leave town on the evening of April 20, but practically on his way out the door, he heard someone knock. It was Weizsäcker’s wife, visibly distraught. She said that her husband had left their home several hours ago on his bicycle to pick up some equipment at his lab and hadn’t returned. Had Heisenberg seen him?
No, he said. You’re sure he’s not somewhere else? She was sure, so he invited her in to wait. They spent the next hour drinking wine and halfheartedly reassuring each other that her husband was fine. Yet with mobs of soldiers and Nazi werewolves roaming about—one historian described the final weeks of the Third Reich as “a complete breakdown of military and civilian order”—they eventually stopped believing their own words. With every minute that passed, the odds increased that something awful had befallen the diplomat’s son.
Weizsäcker finally returned just after midnight. He was unharmed and had no idea he’d caused his wife and friend such distress. Although relieved, Heisenberg said a hasty goodbye to the Weizsäckers and left town at 3 a.m.
With no other means of transportation, he had to pedal a bicycle 150 miles east to his family’s cabin, the Eagle’s Nest. By this point in the war, Allied planes were gunning down even bicyclists, so he traveled at night. He covered roughly fifty miles between each sunset and sunrise, and spent each day concealed in hedgerows, both hands gripping his bicycle while he slept, lest someone steal it. He tried not to talk to anyone, scrounging food from farms and orchards like a criminal on the lam, and he gave a wide berth to the roving bands of foreign troops in the area. He also encountered a wandering platoon of fifteen-year-old German soldiers, lost and hungry and crying.
Despite his caution, an SS guard caught Heisenberg on the final night of his hegira. The guard demanded to know why an able-bodied man like him wasn’t with his Volksturm unit, defending the Reich. He then asked for Heisenberg’s papers. With a sinking feeling Heisenberg dug through his pockets and produced them. The documents excused him from military duty, but they were crude forgeries—no better than a schoolboy’s “doctor note,” and the SS man knew it.
This all but sealed Heisenberg’s fate: he would be shot for deserting. But before the SS man laid hands on him, Heisenberg decided to gamble. He would bribe the soldier, using the one currency that anyone in this whole crazy war would accept, no questions asked—American cigarettes. “I’m sure you haven’t smoked a good cigarette in a while,” he said, removing a crumpled pack of Pall Malls from his pocket. He held out an unsteady hand in the dark.
The SS guard had his duty to carry out: Heisenberg had betrayed the Reich, and the very notion of a bribe was offensive. But the prospect of smooth American tobacco proved overpowering. Despising Heisenberg, and himself even more, he grabbed the pack and waved the physicist on.
Heisenberg arrived at the Eagle’s Nest filthy and exhausted. Yet however glad she was to see him, Elisabeth Heisenberg had little sympathy for Werner. While he’d been gallivanting around Europe the past few months, eating fancy dinners in Zurich and tinkering with Uranium Machines, she’d been stuck with their six children in the tiny cabin, which despite its grand name was rather dilapidated. The previous winter the roof had collapsed from excess snowfall, and they’d had to scavenge tiles from their old home in Leipzig to patch it up. Worse, she struggled to gather firewood in the mountains, and she could neither grow much food in the poor soil nor buy it from stingy local farmers. Elisabeth and the children suffered from constant bouts of illness as a result—and not just sniffles, but serious ailments like scarlet fever.
Chastened, Heisenberg did his best to protect his family now that he was there. He and Elisabeth stacked sandbags in front of the cellar windows for protection from blasts and set about buying as much food as they could afford. Heisenberg had also moved his elderly mother into a cottage in the area, and he made several trips to check on her. Then the Heisenbergs hunkered down to wait out the endgame of the war. Stray bullets still whizzed by the cabin sometimes, smashing into trees, and a local SS unit hanged sixteen men for desertion. Hundreds of soldiers nevertheless tried to escape through the woods, and more than once Elisabeth found her children playing with discarded guns.
The only pleasurable moment that week occurred on May 1, when the Heisenbergs heard the news of Adolf Hitler’s suicide. The previous summer, Heisenberg had despaired while listening to the radio at the cabin, convinced he’d be rounded up in the Wednesday Club conspiracy. Now he could relax at last, and he and Elisabeth celebrated with a bottle of wine they’d been saving for one of their children’s baptisms. After that, they could only wait for what came—and hope like hell that the Americans got to him before the Germans or Russians.
CHAPTER 57
Triumph and Loss
Werewolves—of course it was werewolves. Lightning-A had spent the past few days tracking the scent of Werner Heise
nberg across southern Germany. Their jeeps and armored cars had crossed hundreds of miles of war-torn land, weaving around pockets of Nazi troops and careening over hill and dale. Even a freak spring blizzard in the foothills of the Bavarian Alps hadn’t slowed them down. Now, just miles short of their destination, they were stuck. A pack of teenage Werwolfen had blown a bridge across a gorge, cutting off the only road forward.
Pash sent orders down the mountain to summon a team of engineers to rebuild it. But it would take at least a day to fix, and waiting around all day wasn’t Boris Pash’s style. So he grabbed a handful of doughty men and, taking a page from the Norwegian heavy-water commandos, scaled the gorge in front of him. He then plunged into the mountains to hunt Werner Heisenberg on foot.
According to Pash, his crew looked less like traditional alpine mountaineers and more like “Pancho Villa bandits, with ammunition tucked in pockets and cargo bandoliers slung across our shoulders.” Though it was May, the snow reached halfway to their knees, and every so often they had to flush out pockets of enemy soldiers. Because Pash had neither the time nor the personnel to handle prisoners, he simply slit the waistbands of their trousers so they couldn’t run or fight and ordered them down the mountain to surrender. One man endured even deeper humiliation. Despite reports of Hitler’s suicide, rumors were swirling that the Führer had faked his death and fled into the mountains. Sure enough, Lightning-A captured one German who was the spitting image of Adolf. But upon stripping the man down to his skivvies, they turned him loose. Hitler, everyone agreed, would never wear such ratty underwear.