In the early hours of May 10, 1940, the world witnessed a breathtaking spectacle that would go down in history as one of the most audacious military operations of World War II. Soldiers stationed at the seemingly impregnable Belgian fortress of Eben Emael looked up at the sky to witness an eerie sight—nine unconventional aircraft with slender wings silently descending upon them. In a matter of seconds, these aircraft came to an abrupt halt, deploying 54 elite German airborne soldiers onto the grassy roof of the fortress. In less than half an hour, the supposedly impervious fortress was brought to its knees, setting the stage for one of the war’s most remarkable victories.
To truly appreciate the significance of Fortress Eben Emael, we must journey back to the onset of World War I. According to the German Schlieffen Plan, Germany intended to outflank the French by invading Belgium, which was a neutral nation at the time. Despite the formidable fortifications guarding the strategically vital city of Liege in Belgium, these defenses crumbled swiftly under the relentless assault of massive German siege weapons. The German Army marched unimpeded through Belgium, setting the stage for a new era of warfare. In the aftermath of World War I, neighboring countries, keen to prevent a repeat of 1914, embarked on the construction of sophisticated border fortifications, most notably the famed French Maginot Line. Belgium, investing over twenty-four million Francs between 1932 and 1935, modernized the Liege fortifications, with Fortress Eben Emael at its forefront.
Situated on a diamond-shaped embankment spanning approximately one thousand meters in length and nine hundred meters in width, Fortress Eben Emael was a formidable military installation. It was flanked by the Albert Canal to the east, the Geer River to the west, and a ten-meter-deep antitank ditch to the south. Six reinforced-concrete artillery casemates, armed with 75mm cannons, were strategically positioned atop the fort—Maastricht 1 and 2 to the north, Visé 1 and 2 to the south, and Canal 1 and 2 along the Albert Canal banks, armed with 60mm antitank weapons. The fortress also featured Cupole 1 and 2, each mounting 75mm guns, and the formidable Cupole 120 equipped with 120mm cannons. Complementing these were three massive retractable rotating turrets, known as “cupolas.” Additionally, three other blockhouses—Mi-1 and Mi-2 with machine guns and Block 1 at the fort’s entrance, armed with a machine gun, an antitank gun, and a searchlight—strengthened the fortress’s defenses.
The fortress boasted an intermediate level for transporting personnel and ammunition and a lower level that housed barracks, kitchens, infirmaries, and ammunition magazines. A network of 4.5 kilometers of underground tunnels on two levels connected these strong points. Positioned strategically to safeguard vital bridge crossings over the Albert Canal, the fortress’s batteries were coordinated with those of neighboring forts, enabling mutual fire support in case of enemy attack. Fortress Eben Emael was garrisoned by approximately 500 soldiers, with an additional 500 held in reserve in the nearby village of Wonck.
With such formidable defenses, it is no wonder that Fortress Eben Emael was considered nearly impregnable and loomed large in the strategic considerations of the German High Command in the late 1930s.
German Strategy and the Fall Gelb
In 1940, Adolf Hitler’s plan for invading Western Europe, codenamed Fall Gelb or “Case Yellow,” called for the German Army to bypass the heavily fortified Maginot Line by advancing through Belgium and the lightly defended Ardennes region. However, to execute this plan, the German Army first had to traverse the Albert Canal, a task made seemingly impossible due to the formidable defenses of Fortress Eben Emael.
As German planners delved deeper into Belgium’s defenses, the challenge of neutralizing Fortress Eben Emael appeared insurmountable. Hitler himself contemplated the dire situation, searching for a solution from the highest echelons of the German military. Faced with the prospect of failure, Hitler sanctioned an audacious solution that would become the linchpin of the operation: capturing the fortress from the air.
Germany’s Secret Weapons
The concept of deploying paratroopers, or Fallschirmjäger, was not new. The Soviet Union had demonstrated the idea in 1934. However, it was the Germans who first operationalized it effectively. In 1936, Germany formed the 7th Flieger Division, the world’s first specialized airborne unit, under the command of Generaloberst Kurt Student. In April 1940, as part of the German invasion of Denmark and Norway, Fallschirmjäger took control of crucial airfields and bridges in operations that marked the world’s first combat use of paratroopers.
Hitler summoned General Student to the Reich Chancellery on October 27, 1939, and posed a pivotal question: Could Fortress Eben Emael be captured by deploying paratroopers onto its roof? Initially skeptical due to the technological limitations of the time, General Student questioned the feasibility of accurate parachute landings, as weapons and equipment had to be dropped separately in containers. This process risked losing the element of surprise and would necessitate paratroopers regathering and equipping themselves, a perilous delay. Moreover, even if a small group of lightly armed paratroopers could land on the fortress, what hope could they have against a stronghold designed to withstand even the most powerful artillery?
As General Student pondered Hitler’s challenge, he realized that Germany possessed two secret weapons that could potentially turn the audacious plan into reality.
The Attack Glider and Hollow Charge
The first of these secret weapons was the attack glider, a groundbreaking innovation. In preparation for the formation of a new German Air Force, or Luftwaffe, despite the constraints of the Versailles Treaty of 1919, Germany established hundreds of gliding schools and clubs across the country. These institutions trained pilots in sailplane gliding, providing the nucleus for the future Luftwaffe. The German Research Institute for Sailplane Flight, or DFS, developed the DFS 230, the world’s first combat glider. This silent glider, towed into the air by a Junkers Ju-52 transport aircraft, could glide for up to 12 miles and deliver ten fully armed paratroopers with pinpoint accuracy to their target.
The second secret weapon was the hollow charge, a conical cavity lined with copper containing a 50-kilogram explosive charge. When detonated, this charge transformed the copper cone into a high-velocity jet of molten metal capable of penetrating 25-inch-thick concrete or steel. Paired with flamethrowers to neutralize bunkers, glider-borne troops armed with hollow charges proved the ideal recipe for dismantling the world’s most powerful fortress.
General Student wasted no time. He assembled a formidable group of 480 Fallschirmjäger, named Sturmabteilung Koch after their leader, Lieutenant-Colonel Walter Koch. The plan demanded precise timing and close coordination among four groups—Steel, Concrete, Iron, and Granite. Steel, Concrete, and Iron were tasked with seizing control of canal bridges at Veltzeldt, Froenhoffen, and Canne, preventing their destruction by the defenders. Meanwhile, Granite’s mission was to land on the fortress and eliminate its blockhouses and cupolas, ensuring the fortress’s cannons could not fire on the occupied bridges. Subsequently, all four groups were to hold their positions until relieved by German ground forces.
Training commenced in November 1939, using Czech border fortifications as stand-ins for Eben Emael’s blockhouses. Secrecy was paramount—paratroopers were not informed of their target and trained in plain clothes without insignia. They even practiced with concrete blocks fitted with handles instead of the top-secret hollow charges. Glider pilots honed their precision landing skills, but encountered a major obstacle—the gliders required an extended skidding distance, increasing the risk of rooftop crashes on the small fort. After rigorous testing, it was determined that wrapping barbed wire around the glider’s landing skid at a specific distance could reduce landing distance significantly. By early 1940, training was complete, and paratroopers awaited the signal to execute the audacious assault.
A Triumph of Precision and Courage
In the early hours of May 10, 1940, as darkness shrouded the landscape, the signal was received. At 3:30 in the morning, members of Sturmabteilung Koch rose, donned their gear, and embarked on their gliders. Less than an hour later, Ju-52 towing aircraft roared down the runway, lifting into the sky. The transport aircraft were guided to their release points by a line of ground flares, avoiding the use of radio signals that might alert the enemy. However, almost immediately, the operation encountered complications.
A misunderstood signal led to the premature launch of one glider, forcing it into an emergency landing near Duren, Germany. Simultaneously, the glider carrying Lieutenant Rudolf Witzig, leader of Group Granite, experienced a tow line break, requiring an emergency landing near Cologne. Consequently, Group Granite was left with only nine out of eleven gliders and 54 out of 85 troops. As they crossed the Dutch border, several gliders veered off course and came under anti-aircraft fire, with one suffering severed control cables and plummeting twelve meters to the ground, causing injuries.
Despite these early challenges, the daring operation was underway, and the fate of Fortress Eben Emael hung in the balance.
The Precision Assault
The audacious raid on Fortress Eben Emael was a masterclass in precision and courage. As Sturmabteilung Koch faced adversity, their resolve remained unshaken. Join us as we delve deeper into the remarkable events of that fateful day and uncover the secrets behind the triumph of ingenuity and daring. Discover the remarkable individuals and innovations that made this legendary raid a pivotal moment in military history.