The Ardennes Highlands have been a historically strategic location in Central Europe, situated in the southeastern part of Belgium, northern Luxembourg, and northeastern France, covering an area of approximately 10,000 square kilometers. Due to its dense forests, it is also known as the Ardennes Forest.
Although the roads in the Ardennes Forest are rugged, Manstein, after consulting tank expert Guderian, confidently asserted that, given the excellent military qualities and high mobility of the German army, large tank formations could smoothly pass through the Ardennes mountain pass.
The French, on their part, were aware that the Ardennes Forest might become a breakthrough point for the German army. Even in a 1929 French exercise, a commander of armored units led his forces through the Ardennes Forest in 60 hours. However, the terrain of the Ardennes Forest was not conducive to large army movements, especially for the then clumsy French armored units. Consequently, the original plan to deploy infantry divisions and anti-tank guns in this area was reduced to a light infantry division, serving mainly for patrol and vigilance.
The French anticipated the possibility of the German army attacking France through the Ardennes Forest before the war. However, they did not pay much attention to it. They preferred to allocate millions of troops to the seemingly impregnable Maginot Line rather than station any significant forces in the Ardennes Forest. On the one hand, France relied too much on the terrain of the Ardennes Forest and underestimated the mechanized capabilities of the German army. On the other hand, if the German army did not use the Ardennes Forest, then every soldier stationed there would be surplus. Due to France's lack of attention, when the German army crossed the Ardennes Forest, they faced minimal resistance. The German army traversed the Ardennes Forest in less than 60 hours, bringing the flames of war to France.
No matter how treacherous the terrain, its defensive efficacy is only realized when armed forces are present to defend it. Otherwise, it's no different from an endless expanse. France didn't lose in the Ardennes Forest due to its inhospitality; it lost because of its inexplicable sense of luck.
At this moment, in the Ardennes Forest considered an insurmountable barrier by the French, hundreds of German reconnaissance soldiers are cautiously advancing. They have been navigating this forest for a day and a night, searching for a route that can accommodate armored units.
"Cut down that tree in front!" A sergeant leading one of the squads pointed to a towering tree ahead, giving the order.
They don't bother with ordinary-sized trees that tanks can easily break through. They need to deal with the towering trees that have been growing for decades.
A scout with a chainsaw walked over.
"Bzzz." As the rapidly spinning chainsaw teeth approached the tree trunk, sawdust scattered, and the chainsaw emitted plumes of black smoke. Throughout their journey, they had lost count of how many trees they had sawn down, maxing out their tree-cutting skills. In no time, the decades-old giant tree slowly fell, crashing heavily to the ground.
The other reconnaissance soldiers rushed forward, sawing the large tree into several sections and pulling them aside.
"Continue forward!"
Sometimes they were very lucky to encounter a stretch of terrain that required no clearing, allowing tanks to pass directly.
After almost three days of walking, they finally saw the forest ahead gradually thinning. This indicated that they were nearing the edge of the forest.
Several reconnaissance soldiers cautiously moved forward until they saw a distant French outpost beyond the forest. They turned back. "There are no big trees ahead; tanks can pass through directly."
"Great! Report to headquarters quickly. The tank unit can pass through the forest!"
At this moment, there was a tense atmosphere in the Berlin headquarters.
Field Marshal Rundstedt's eyes were somewhat reddened; he had hardly closed them in the past few days. After all, this was a decisive battle against the self-proclaimed "top power in Europe", France, and the foremost naval power, Britain. This battle could be considered crucial for the destiny of the empire for centuries to come.
While he anxiously paced back and forth, a staff officer hastily walked in. "Field Marshal, the reconnaissance troops in the Ardennes Forest have reported that they have found a route passable for tank units. The intelligence department also received information that France has shifted all its forces to Belgium, without even leaving a reserve."
"Excellent!" Cheers erupted in the room. With the discovery of this route, the success of the surprise attack plan was already halfway achieved. As the main forces of France and the British Expeditionary Force were stationed in the vulnerable Belgium, the sudden appearance of the German armored units in their rear would undoubtedly throw them into disarray.
Field Marshal Rundstedt couldn't help but breathe a sigh of relief and picked up the phone. "Your Highness, a route through the Ardennes Forest has been found. We can launch the attack at any time now."
"That's good. I'm waiting for good news; you can set off immediately afterward."
At noon that day, the Imperial Foreign Minister Ribbentrop delivered a speech titled "Peace or War", harshly condemning the actions of England and France, claiming that they were dragging Europe into the pit of war. He warned that England and France had six hours to revoke the declaration of war and withdraw the Anglo-French coalition troops stationed in Libya.
By now, England and France, already ensnared in Wilhelm's "Yellow Plan", naturally paid no attention to Germany's warning. According to the operational attempt outlined in the "Yellow Plan", Germany planned to launch a major assault on France and its allies through Belgium. Ribbentrop's speech served as evidence supporting the authenticity of this "Yellow Plan."
This was exactly what Wilhelm hoped for. After all, if England and France obediently withdrew the declaration of war, then he would lose the element of surprise, and how could the war continue?
As for the good news he was waiting for, it was the secret dispatch of the U-47 submarine to Scapa Flow.
Scapa Flow is a semi-enclosed water area located at the northernmost tip of the Orkney Islands, Scotland, within the United Kingdom. It is surrounded by the main island, Hoy Island, South Ronaldsay Island, and several smaller islands, constituting a natural and well-protected harbor with a length of about 24 kilometers, a width of 13 kilometers, and an area of 130 square kilometers. It served as a vital naval base for the Royal Navy, controlling the North Sea from ancient Viking times until the Royal Navy closed the port in 1956.
Scapa Flow witnessed two notable events: first, at the end of World War I, the defeated German Imperial Navy scuttled its main fleet of 51 ships, including battleships, battlecruisers, cruisers, and destroyers, totaling 400,000 tons, in Scapa Flow in an operation known as the "Operation Rainbow."
The second event was the mysterious ghost of Scapa Flow.
Scapa Flow was heavily guarded, and the British stationed a large number of troops for defense. Onshore defenses included hundreds of large-caliber cannons and dense anti-aircraft firepower.
In World War I, two German submarines attempting to infiltrate the harbor met tragic ends. On November 23, 1914, SM U-18 submarine ran aground in the harbor, and all crew members were captured. On October 28, 1918, SM U-116 submarine was detected by underwater listening devices and subsequently sunk, with all crew members sacrificed. These two incidents led senior British naval officials to believe that any attempt to break through Scapa Flow was absolutely impossible.
However, Dönitz didn't believe in superstitions. Analyzing high-resolution photographs taken by German reconnaissance planes, he deduced that although Scapa Flow had numerous anti-submarine nets and sunken ships, there were clear gaps. If timed correctly, submarines could quietly pass through the gaps on the calm surface of the water, slipping into the harbor at night.
It was an extremely dangerous mission but not impossible.
A German U-boat commanded by Captain Günther Prien silently slipped into Scapa Flow. It launched six torpedoes at the Royal Oak battleship in succession.
In the first wave, one torpedo hit the bow of the Royal Oak, causing minor damage and not arousing significant commotion onboard. Ironically, the awakened British sailors didn't pay much attention; they believed it was an explosion in a storage room containing kerosene or a paint room. This was because the battleship Vanguard had experienced a similarly mysterious explosion in Scapa Flow before. Consequently, most sailors went back to sleep, completely unaware that they were under attack by a German submarine.
In the second wave of three torpedoes, all of them hit their mark. The Royal Oak battleship, engulfed in a fierce explosion, sank to the seabed in a matter of minutes, with 833 people perishing, including Rear Admiral Henry Blagrove, commander of the Second Fleet. Only 386 people were rescued, including Captain William Benn.
Initially, the British believed that the Royal Oak had suffered an accidental internal explosion. It was only later that they realized it was a German submarine attack. By then, U-47 had already embarked on its journey home. Two days later, Prime Minister Churchill officially announced the sinking of the Royal Oak, acknowledging that the German submarine's raid was a bold and professional operation.