5 Famous WWII Covert Operations

Along with its massive field campaigns, World War II also played host to an underground brand of warfare that included espionage, sabotage, disinformation and special operations behind enemy lines. These cloak-and-dagger tactics resulted in some of the most ingenious and unconventional missions of the war, and played a vital role in the outcome of several major battles. From the spy that never was to a band of Nazi impostors, learn the stories behind five of the boldest and most bizarre special operations carried out during World War II.

1. Operation Mincemeat

Phony ID card for "William Martin" (Credit: Getty Images)

In April 1943, the waterlogged corpse of a British Royal Marine was found floating off the coast of Spain. The dead Brit had a suspicious-looking attaché case chained to his wrist, and this soon caught the attention of the Germans, who colluded with pro-Nazi elements in the Spanish military to surreptitiously gain access to its contents. Inside they found a shocking letter to a British officer in Tunisia outlining a secret Allied scheme to stage an invasion of Sardinia and Greece in the coming weeks.
The dead man’s documents would have been a major intelligence coup for the Nazis, if not for one small issue: they were all fakes. As part of a plan dubbed “Operation Mincemeat,” British spymasters had dressed the body of a deceased tramp in the guise of a fictitious Allied courier named William Martin. After the corpse’s briefcase was stuffed with phony military plans, a Royal Navy submarine secretly deposited the body off Spain in the hope that it might hoodwink the Nazis. The result was the perfect con: not only did the Germans intercept what they believed to be crucial information about where the Allies would attack the Mediterranean, they were convinced they had done so without tipping off the British. Duped by Operation Mincemeat’s bogus intelligence, Hitler diverted tank divisions and other personnel to Greece, only to be caught off guard in July 1943, when the Allies instead invaded Sicily and Italy with some 160,000 troops.

2. Operation Eiche

Benito Mussolini and Otto Skorzeny shortly after Mussolini's rescue (Credit: Roger Viollet/Getty Images)

Also known as the “Gran Sasso Raid,” 1943’s Operation Eiche saw a team of German commandos pull off the daring rescue of none other than Benito Mussolini. The mission came in the wake of the Allied invasion of Italy, which had resulted in the fascist dictator being expelled from office and arrested by the king of Italy. Concerned that Mussolini was crucial to keeping Italy in the war, Adolf Hitler ordered Waffen SS officer Otto Skorzeny to free “Il Duce” before he could be handed over to the Allies as part of a peace deal. After several false starts and dead ends, Skorzeny and his team tracked Mussolini to the Hotel Campo Imperatore, a ski resort situated on a remote mountaintop in the Apennine range.
With no easy way to reach the resort from the ground, Skorzeny opted for a risky aerial attack. On September 12, 1943, he and a team of commandos made a silent descent on the mountain in twelve gliders and stormed the hotel, easily overwhelming the bewildered Italian guards. After destroying the post’s radio equipment, the commandos located a much-relieved Mussolini, who supposedly exclaimed, “I knew my friend Adolf Hitler would not leave me in the lurch!” Desperate to make his getaway before reinforcements could arrive, Skorzeny convinced one of his support aircraft to make a precarious landing on the rugged mountaintop and then personally escorted Mussolini to safety in Austria. The dictator went on to spend several months as a puppet leader in northern Italy before partisan forces finally captured and killed him in April 1945.

3. Operation Gunnerside

The Norsk Hydro Vemork plant

The little-known Operation Gunnerside began in February 1943, when a small team of British-trained Norwegian exiles parachuted onto a frozen plateau near the Norsk Hydro Vemork plant in Norway. At the time, the Nazi-controlled site was the world’s only significant producer of heavy water—a substance crucial to the development of atomic weapons. The plant had already allowed the Germans to make progress in their atomic research, and Winston Churchill and the Allies were desperate to deny the Nazis any chance at developing an atom bomb.
On the night of February 27, the Norwegian commandos skied to the Norsk Hydro site, descended a gorge, forded an icy stream and made a perilous climb to the outskirts of Vemork. After bypassing German sentries and minefields, the men entered the plant through a cable duct and planted explosive charges on the heavy water chambers. As the crew made their getaway, the bombs detonated and successfully destroyed the facility. Operation Gunnerside only crippled German heavy water production for some six months, but it wasn’t the last Norwegian act of sabotage against German atomic research. In February 1944, resistance agents used explosives to sink a boat as it tried to ferry a large supply of heavy water to Germany.

4. Operation Greif

Otto Skorzeny in his jail cell, 1948. (Credit: Gamma-Keystone/Getty Images)

During the early stages of December 1944’s Battle of the Bulge, Adolf Hitler dispatched commando leader Otto Skorzeny—already famous for his September 1943 rescue of Benito Mussolini—on a secret mission to wreak havoc on Allied communications and morale. As part of “Operation Greif,” Skorzeny disguised a small collection of English-speaking Germans in captured American uniforms, provided them with forged U.S. Army documents and sent them on an undercover mission behind enemy lines. In a matter of days, the sham soldiers had successfully directed tank and convoy traffic down the wrong roads, destroyed ammunition dumps, switched road signs and destroyed telephone lines—all right under the Allies’ noses.
While Skorzeny’s commandos failed to achieve any significant military objectives, their hijinks were successful in inciting confusion and panic within the American ranks. As word of the phony troops spread, American soldiers set up checkpoints along major roads and began quizzing their fellow G.I.s on baseball and pop culture in the hope of outing the impostors. The security stops only heightened the chaos. Many Allied troops were briefly arrested or detained, and operations briefly ground to a halt. When a few of the Germans were captured in the dragnet, they kept up the ruse by claiming a commando team was en route to Paris to murder General Dwight D. Eisenhower. As a result, the Allied commander was briefly kept under house arrest to protect him from would-be assassins. Skorzeny’s remaining commandos finally withdrew from behind enemy lines in late December after the Nazi offensive stalled, but the Allies’ would continue their frantic search for German impostors for several more months.

5. Operation Fortitude South

Dummy Allied tank (Credit: Barcroft Media via Getty Images)

D-Day was one of the largest land invasions in military history, but it was preceded by an equally elaborate campaign of subterfuge known as Operation Fortitude South. Spearheaded by the British, Fortitude South was a ruse designed to deceive the Germans into thinking the Allies would make landfall in France at the Pas de Calais instead of Normandy. To help sell the con, the Allies created a fictitious invasion force known as the “First U.S. Army Group” and fed the Germans phony intelligence suggesting the phantom army would lead a charge on the Pas de Calais. Operatives used inflatable tanks, wooden airplanes and dummy fuel depots to trick reconnaissance pilots into believing that the First U.S. Army Group was assembled in Kent, England—the most likely staging ground for an attack on the Pas de Calais. To top it all off, they even placed the much-feared General George Patton in charge of the fake army to lend it an additional air of authenticity.
Operation Fortitude South continued even after the Allies launched their invasion of Normandy on June 6, 1944. Aircraft focused many of their bombing runs on the Pas de Calais instead of Normandy, and double agents worked to convince the Germans that the D-Day invasion was merely a feint designed to screen a second, larger offensive from the south. The swarm of contradictory reports, bluffs and misdirects ultimately had their intended effect. When the Allies stormed the beaches at Normandy, the Germans had a large concentration of troops languishing at the Pas de Calais, waiting for an assault that never came.