Nazi Megaweapons — A Concrete Tale

I just finished watching the National Geographic/PBS documentary series Nazi Mega Weapons, also known as Nazi Megastructures. I knew the Nazis in World War II led the world in the development of revolutionary weapons systems such as the first jet fighter, the first ballistic missile, the first cruise missile and the first true submarine.

What I didn’t realize was behind every super weapon was a pile of super large concrete. The Nazis loved concrete. They had to. They were constantly being bombed. Their engineers were masterful at using the material to build fortifications, tunnels and underground complexes. Concrete also tied into one of Hitler’s chief quirks – he loved big things, and not just big, but the biggest. That meant Nazi concrete structures built to protect their super weapons became massive projects. The remnants of this particular war history can still be seen today although the concrete is generally overgrown with vegetation, moss-covered and partially flooded.

Cement v. Concrete

Unhandy people like myself use concrete and cement interchangeably but that’s not correct, I’m told. Concrete is made up of three components: water, aggregate (rock, sand, or gravel) and cement, which is a binding agent. Experts believe cement was first used in 5,600 B.C. Egyptians, Greeks and Romans used cement and crude forms of concrete. The Romans even discovered a mixture that would set underwater. Concrete can absorb tremendous compression forces (weight) but is brittle when stretched.

European engineers in the 19^th century added tensile strength to concrete by embedding reinforcing steel wires, bars or mesh (rebar). After that, reinforced concrete could be used to build about anything (including a concrete boat) but became extremely popular for skyscrapers, bridges and roads. Or if you’re a Nazi, for forts, bunkers, tunnels and underground factories. And if you’re a Nazi wanting Hitler’s approval for your project, make it the biggest concrete structure you can.

Hitler’s 1,000-year Third Reich only lasted 12 years, but his concrete structures could very well be around in 3019, much like Roman aqueducts and coliseums.

Resource intensive

While the Nazi mega weapons and their protective concrete megastructures were undeniably impressive, the documentary points out a mega flaw. Both the weapons development and the infrastructure were incredibly expensive, time-consuming and resource-wasting.

And the evil underlying all the construction: It would not have been possible except for thousands of slave laborers and concentration camp inmates, many of whom perished from malnutrition, exhaustion and executions. The SS commanders in charge of constructing the bunkers, tunnels and underground complexes were tracked down after the war. Some killed themselves while others were tried as war criminals and executed.

The Nazi quality versus Allied quantity gamble also didn’t pay off. There were simply not enough missiles, jet fighters, super submarines and mega tanks to stem the Allied onslaught. And of course Hitler completely whiffed on the biggest mega weapon of them all – the atomic bomb. He encouraged Jewish atomic physicists to leave Germany, which they did and immigrated to Britain or America where they built the bomb.

Lots of concrete

Here are some short abstracts of some of the biggest Nazi megastructures.

The Atlantic Wall Not just the French coastline but 3,000 miles from Norway to the Spain/France border containing 15,000 bunkers manned by 300,000 troops. The WW II fortifications – the largest fort system in history – took 40 million tons of concrete to build 500 different types of bunkers. The Atlantic Wall was constructed by the Todt Organization, which built the famous German autobahn. Hitler called on Fritz Todt for many other concrete projects like the Siegfried Line along the French/German border and the U-boat submarine pens. It was the Todt Organization that turned Nazi megastructure construction into an efficient assembly line operation, using forced labor of course. Fun fact: the very first gun position in the Atlantic Wall was built at Calais and was designed for offense, not defense. In preparation for an invasion of Britain that never came, the cannon fired large shells across the English Channel and destroyed 10,000 buildings. The Atlantic Wall was breached on D-Day June 6, 1944, in four or five hours.

U-Boat Pens German U-boat pens along the French coast are now tourist attractions. The documentary highlights the massive submarine base in the Breton city of Lorient. Containing 3 million tons of reinforced concrete and manned by 15,000 people, it contained a bomb-proof double chambered roof 3.5 meters thick. Fun fact: we know it was bomb proof because one of England’s “Tall Boy” bombs (Britain loved large, unusual bombs) containing 2 tons of explosives struck the roof, penetrated the first layer but failed to dent the second roof layer or the interior. The pens protected Hitler’s most effective weapon in WW II, the dreaded Type VII U-boat, which almost won the war. The U-boats were defeated at sea, not in their pens. The troops in the massive Lorient structure held out until two days after the German surrender in May 1945.

Reimahg ME-262 aircraft factory Willy Messerschmitt’s revolutionary jet fighter needed protection from Allied bombers so production was scattered around Germany. An efficient, central assembly point was envisioned so the Germans turned a porcelain mine under the Walpersberg mountain in Kahla in central Germany into an underground assembly line. Some 12,000 slave laborers (over a thousand perished) built nine miles of tunnels that were supposed to produce 750 jets a month. Fun fact: part of the complex was a runway on top of the mountain. An elevator hoisted finished jets to the top where they took off. Trouble was, only 26 Me-262 jets were finished at Reimahg. Another example of too little, too late.

Mittelwerk V-2 Rocket factory For some reason, the Germans thought the world’s first rocket base at Peenemünde, which in itself was a sprawling complex of large concrete structures, would not attract attention with dozens of rocket tests flying into the ocean and exploding. It did and the British flattened the place in a bombing raid that killed dozens of scientists and staff. So the Nazis turned to their old friend, bomb-proof concrete. They constructed a domed rocket base in La Coupole, France, which still exists, where 55,000 tons of concrete was used to build 7 kilometers of tunnels and a six-story tall assembly chamber. La Coupole was supposed to launch 15 V-2s a day but never fired one because it was bombed and in the path of invading Allied armies. The Nazis turned to mobile launchers that were much more successful. The Allies never caught a mobile launcher on the ground, and the Germans were able to launch 3,000 rockets between Sept. 8, 1944, and March 27, 1945. There was no defense against the supersonic V-2s that killed or wounded nearly 7,000 people in London and Antwerp, but since they weren’t very accurate, they were mainly used as a terror weapon that had little effect on the war. And now the concrete story. The Nazis had to have a safe place to assemble the rockets so 60,000 concentration camp inmates (20,000 died) built and manned the Mittelwerk rocket factory in a former gypsum mine near Thuringia, Germany. Two 6,200-feet long main tunnels were intersected by dozens of cross tunnels totaling 1 million square feet of factory space. Fun fact: The V-2 program cost 500 billion reichs marks, an astronomical sum that barely pricked the Allied juggernaut. Talk about warped cost-benefit ratio. As Warhistorybuffs know, Wernher von Braun, his two brothers, and dozens of other German rocket scientists moved to the U.S. after the war where in a little over 20 years their rockets sent American astronauts to the moon.

Valentin Submarine pen This structure on the Weser River near Bremen was not just any submarine pen for just any submarine. This ¼ mile-long building was supposed to be an assembly line for the revolutionary Type XXI U-boat. The concrete numbers are staggering: 650,000 cubic yards of the stuff was used to construct 15-foot thick walls, and gigantic concrete arches that finished the 15-foot thick roof in the 90-foot tall building. At least 8,000 forced and slave laborers including prisoners of war worked on Valentin and nearly 2,000 perished. Fun fact: the submarine pen was never used. The British and their big bombs struck the site, and one of their 10-ton “Grand Slam” bombs partially penetrated the roof and scattered debris on the floor of the facility. Valentin was divided into 13 bays for assembling pieces of the Type XXI hull. The 13th bay could be flooded to launch a completed U-boat. After the bombing, the submarines had to be constructed in pieces at various locations around Germany and assembled on the northern coast. The Type XXI was truly remarkable. It could travel 17 knots underwater and stay submerged 11 days versus one or two days for the Type VII U-boat. The hull design was so advanced it was used as a model for the USS Nautilus, the world’s first nuclear-powered submarine. Technological and construction issues along with training delays meant only two Type XXI were deemed seaworthy. Which was a lucky break for the Allies. After the German surrender was announced, the Type XXI U-2511 went completely undetected as it sailed under a British cruiser and four escorts.