Divers Tried To Defuse Poland’s Largest WWII Bomb – But The Explosive Detonated In The Process

There is a bomb in the Polish city of Świnoujście. The residents fear for their lives. They flee their homes and take shelter in a mass evacuation center. Yet this isn’t Europe at the height of World War II. It’s 2020, and the area is being cleared as experts strive to quickly defuse an unstable Tallboy explosive. Below the waters of a canal, divers attempt to carefully dismantle the volatile contraption. But they will fail. And before long, the device will detonate – resulting in an explosion of epic proportions.

This was a detonation 75 years in the making. The bomb actually arrived during WWII when Britain’s famed Dambuster bomber squadron launched a brutal attack on a German ship moored outside Świnoujście. And while the majority of the explosives hit their mark, one of them sank – undetonated – to the bottom of the canal. It remained there as a silent threat to the people who lived nearby for decades.

Of course, you might think that living near any type of dormant explosive would be enough to jangle the nerves. But in this case, it was no ordinary weapon that threatened the population of Świnoujście. Beneath the waters of the Piast Canal lurked a sleeping Tallboy – a device popularly known as an earthquake bomb. And believe us, the explosive is suitably named.

According to the Barnes Wallis Foundation, the Allies dropped more than 850 Tallboys on enemy targets during WWII – wreaking widespread devastation across Europe. Yet not all of the bombs exploded on impact. And in 2019 one was discovered during work on the Piast Canal, which sits beside the German border. Then military divers began the painstaking process of defusing the bomb – though not everything went to plan, as we’ve heard.

Yes, three quarters of a century after it was dropped, the bomb beneath the Piatz Canal exploded – even as a team of experts worked to defuse it. And in the aftermath of the devastating eruption, there was one question on everybody’s lips. So just how did the device remain so powerful after so many years?

ADVERTISEMENT

The answer lies in the work of British engineer Barnes Wallis. Wallis began his career designing the airships and airplanes that characterized the early days of flight. But when World War II broke out in 1939, he decided to apply his talents to the art of combat instead. A proponent of tactical bombing, he believed that the development of devastating explosives would be key to defeating the Axis forces.

Creative and ambitious, Wallis dedicated himself to developing technology that would help bring the Axis powers to their knees. In 1941 the British government set its sights on destroying German dams, and he was determined to figure out the best approach. But the chosen target – the Möhne Reservoir some 30 miles outside Dortmund – posed a significant challenge.

ADVERTISEMENT

The dam that the Allies wanted to attack stood some 130 feet tall and had a thickness of more than 100 feet in places, according to the Barnes Wallis Foundation. Nevertheless, the eponymous engineer came up with a plan to breach the structure – using little more than a volley of large explosives. But the accuracy required for this to succeed would have been impossible for a bomber to achieve. As a result, the idea of an attack on Möhne was shelved.

Though Wallis would not take no for an answer and continued to dream up plans for a feasible attack. If the explosives could not be dropped from above, he reasoned, perhaps they could be skipped across the water towards the target? By experimenting with marbles, Wallis eventually came up with the idea of a bouncing bomb.

ADVERTISEMENT

Although it might have sounded far-fetched, Wallis’ idea worked, and the plan to launch an attack on German dams was back on the table. Just after midnight on May 17, 1943, the Royal Air Force No. 617 Squadron dropped a series of bouncing bombs above the Möhne Reservoir. Eventually, they succeeded in breaching the massive structure.

Later, the squadron also managed to bomb a hole in the Edersee Dam – some 80 miles south-east of Möhne. Thanks to Wallis’ weapons, German resources were directed towards rebuilding destroyed infrastructure and away from the war effort. And even though more than a thousand innocent civilians died, the attacks are generally viewed as heroic today.

ADVERTISEMENT

Wallis’ reputation was secured after the Dambusters’ attacks. This then enabled him to return to ideas that had initially been rejected. Among these was an invention dubbed the earthquake bomb: a large explosive designed to penetrate deep below the target and detonate underground. Afterward, the engineer believed, the shockwave would cause widespread devastation.

At first, Wallis envisaged a huge, ten-ton bomb that would be dropped on the enemy from a height of 40,000 feet, his foundation explained. But this scheme was too ambitious for the technology that existed at the time. Instead, he settled for an explosive weighing six tons – designed to be released from 18,000 feet.

ADVERTISEMENT

Given the codename Tallboy, Wallis’ ambitious new weapon was first put to the test in France on the night of June 8, 1944. The target was the Saumur railway tunnel – a vital lifeline connecting southern and northern France. Just days earlier, the Allies had landed on the beaches of Normandy, and the bombers were tasked with cutting off access to the site of the invasion.

Once again, the 617 Squadron would be about to make history as it took to the skies over the Loire equipped with 19 Tallboy bombs. Sure enough, its mission devastated the railway line, which prevented German troops from traveling north to fight off the Allies. And from that point onwards, Wallis’ invention played a central role in the British war effort – destroying targets across western Europe.

ADVERTISEMENT

As WWII progressed, the Allies dropped hundreds of Tallboy bombs on enemy targets – destroying buildings, battleships and infrastructure alike. And eventually, it became obvious that the Axis powers were going to lose the war. But the conflict across Europe would continue for nearly a year after the Allied invasion of northern France. And in countries like Poland – where the unexploded device would later be discovered – the fighting was particularly fierce.

That January the Soviet Union had begun its advance into Poland – prompting a mass exodus of German citizens. And by March many of them had gathered in Świnoujście on the north-west coast. Though before the refugees could escape across the Baltic Sea, the United States Army Air Force launched a brutal attack and thousands of civilians were killed.

ADVERTISEMENT

Despite relentless assaults from the Allies, however, the Axis powers continued to fight. And on the Piast Canal outside Świnoujście, the German cruiser Lϋtzow was deployed as part of a last-ditch effort to hold off the Soviets. But the Nazis suffered a serious blow on April 16, 1945, when the Dambusters carried out yet another devastating aerial attack.

This time, the 617 Squadron dropped 12 Tallboys from Lancaster bombers onto the anchored Lϋtzow. But things didn’t exactly go to plan. According to reports, one of the aircraft got into difficulties and eventually crashed on nearby Karsibor Island. And if that wasn’t bad enough, one of the explosives failed to detonate – sinking dormant into the Piast Canal.

ADVERTISEMENT

Luckily, one of the Tallboys scored a direct hit on the Lϋtzow, while several others landed close to the mark. Having sustained extensive damage in the blasts, the vessel sank to the bottom of the canal – leaving just its deck jutting out above the water. For weeks afterward, the Germans continued to use this exposed section as a gun turret. But ultimately, the ship was later scuppered and sold as scrap.

Less than a month after the Dambusters’ attack on the Lϋtzow, Germany surrendered and the war in Europe finally came to an end. The bombs dropped over the Piast Canal, as it turned out, would be among the last Tallboys ever deployed. But the story of Wallis’ deadly explosives did not end there.

ADVERTISEMENT

Fast forward almost 75 years, and Świnoujście has become a popular tourist resort. Instead of refugees desperate to flee across the Baltic Sea, the city is filled with people enjoying relaxing holidays by the coast. Yet in September 2019 workers discovered something that would shatter this peaceful idyll and bring back the horrors of World War II.

That month, a project was underway to deepen the waterway outside Świnoujście. But as the canal was being dredged, a long-forgotten secret emerged – the unexploded Tallboy that had been dropped on the Lϋtzow during World War II. It was reportedly the biggest dormant World War II device ever discovered in Poland, so it must have been a startling sight. But would the bomb still pose a risk to the public so many years after it had been dropped?

ADVERTISEMENT

For almost a year, the Tallboy remained at the bottom of the Piast Canal – its existence looming ominously over the city. Then finally, in October 2020 work began to defuse the dormant bomb. But before experts could start the painstaking work, they needed to secure the area. And according to CNN, that meant evacuating over 750 people from their homes.

Perhaps unsurprisingly, many of the residents of Świnoujście were taken aback by the extreme measures. Speaking to the AFP in October 2020, local Halina Paszkowska said, “I’ve lived here 50 years and there have been other bombs, but this is the first time there’s an evacuation! Before, we just had to stay indoors.”

ADVERTISEMENT

In fact, some of those living in the city told reporters that they intended to defy evacuation orders. But as experts prepared to defuse the 20-foot bomb – which contained around 2.5 tons of explosives – fear began to spread through the community. And ultimately, most people left their homes and took shelter in centers nearby.

On October 12, 2020, a team of sappers from the Polish Navy swam out into the Piast Canal – determined to tackle the dormant bomb. Initially, the plan was to spend the first part of the five-day mission carefully preparing the explosive. Speaking to the press at the time, military spokesman Grzegorz Lewandowski explained, “It’s a very delicate job… The tiniest vibration could detonate the bomb.”

ADVERTISEMENT

But why did the Polish Navy need to defuse the bomb at all? After all, plenty of leftover World War II explosives have simply been detonated in controlled situations and haven’t needed to be meticulously dismantled. But according to Lewandowsky, this was not an option in Świnoujście, due to the presence of a bridge less than a third of a mile from the Tallboy’s location.

So, the divers decided to use a technique called deflagration, which involves simply burning off the explosives without a detonation. By using a remote-controlled device to heat the bomb, they could render the Tallboy inactive without having to be anywhere near the weapon. This, of course, must have been somewhat reassuring. Experts were only 50 percent sure that the operation would be a success, according to the AFP.

ADVERTISEMENT

As it turns out, they were right to err on the side of caution. On October 13, just one day after the operation began, the Tallboy exploded – sending a jet of water into the skies high above Świnoujście. And had any of the team been closer to the blast, they would likely have met with a violent end.

But despite the dramatic appearance of the explosion, experts insisted that the operation had been controlled. The following day, Lewandowski made an announcement on the Ministry of National Defence of the Republic of Poland’s Twitter account. It read, “The deflagration process turned into detonation. The object can be considered neutralized, it will no longer pose a threat to the Szczecin-Swinoujscie shipping channel.”

ADVERTISEMENT

Around the same time, an unnamed spokesperson for the Polish military told CNN, “Every step of [the] operation was under control.” But what was the impact of exploding Wallis’ earthquake bomb in the middle of a built-up area? Surprisingly, reports claim that nobody was injured in the aftermath of the detonation.

There was also apparently no damage to infrastructure sustained during the explosion. And while online commenters speculated on the potential harm to marine life, there appeared to be no evidence of any ill effects springing from the incident. And before long, life in Świnoujście returned to normal.

ADVERTISEMENT

Amazingly, this wasn’t the first time that a long-dormant Tallboy has reared its head long after the end of World War II. Back in January 1959, some 650 residents of Langscheid in West Germany were evacuated from their homes after an earthquake bomb was discovered at the bottom of a reservoir. Ironically, it was also the same organization that had dropped the explosive which was called upon to defuse it.

Fifteen years after the Royal Air Force unloaded the Tallboy over Germany’s Sorpe Dam, a British flight lieutenant helped to defuse it. And if reports are to be believed, he succeeded – this time without causing an explosion. At the time, it was one of the largest explosives ever tackled by any bomb disposal unit.

ADVERTISEMENT

To date, the bombs found in Langscheid and Świnoujście are the only unexploded Tallboys to be unearthed. Yet the former battlegrounds of World War II are littered with leftover ordnance even today. Some of these devices have detonated dramatically over the years, though others may yet be lingering, undiscovered, beneath the ground.

On June 23, 2019, for example, residents of Limburg in Germany reported hearing a loud explosion during the night. And when they awoke, they saw that a huge crater had appeared in a nearby field. On closer inspection, it was revealed that an old World War II bomb had exploded – tearing a hole more than 30 feet across, according to the New Scientist.

ADVERTISEMENT

Luckily, none of these incidents resulted in anything worse than a bad shock for those in the vicinity. But sometimes, things haven’t worked out quite so well. In 2014 construction workers in the German town of Euskirchen accidentally triggered a dormant World War II bomb. Sadly, one man tragically died in the explosion that followed.

But most of the time, thankfully, experts can successfully defuse bombs leftover from old conflicts. And it happens more often than you might think. As recently as 2019, for instance, some 2,000 people were cleared from the streets surrounding Paris’ Porte de la Chapelle train station while experts tackled a 75-year-old explosive. And in 2017 a device found at Frankfurt’s Goethe University prompted the relocation of 70,000 citizens in Germany’s biggest evacuation since World War II.

ADVERTISEMENT

Luckily, it seems as if explosions like the one at Świnoujście are few and far between. But with hundreds of Tallboys dropped over Europe during World War II, can we really be sure that all of them are accounted for? Or might there be another deadly surprise just waiting to be discovered?

ADVERTISEMENT
ADVERTISEMENT