The Battle of Britain

The Battle of Britain, when the British Royal Air Force defended the United Kingdom against the German Air Force attacks, was the first major Nazi defeat and a turning point of World War II.

The Battle of Britain occurred during the Second World War when the Royal Air Force (RAF) defended the United Kingdom against the German Air Force (Luftwaffe) attacks from the end of June 1940. It is described as the first major campaign fought entirely by air forces.

The primary objective of the Nazi German forces was to compel Britain to agree to a negotiated peace settlement. In July 1940, the air and sea blockade began with the Luftwaffe mainly targeting coastal shipping convoys, ports, and shipping centers such as Portsmouth. On August 1, the Luftwaffe was directed to achieve air superiority over RAF with the aim of incapacitating RAF Fighter Command. Twelve days later, it shifted the attacks to RAF airfields and infrastructure. As the battle progressed, the Luftwaffe also targeted factories involved in aircraft production and strategic infrastructure and eventually employed terror bombing on areas of political significance and civilians.

By preventing the Luftwaffe’s air superiority over the UK, the British forced Adolf Hitler to postpone and eventually cancel Operation Sea Lion, a proposed amphibious and airborne invasion of Britain. However, Nazi Germany continued bombing operations on Britain, known as the Blitz. The failure to destroy Britain’s air defenses to force an armistice (or even outright surrender) is considered the Nazis’ first major defeat in World War II and a crucial turning point in the conflict.

Several reasons have been suggested for the failure of the German air offensive. The Luftwaffe High Command did not develop a strategy for destroying British war industry; instead of maintaining pressure on any of them, it frequently switched from one type of industry to another. Neither was the Luftwaffe equipped to carry out strategic bombing; the lack of a heavy bomber and poor intelligence on British industry denied it the ability to prevail.

Battle of Britain: Nazi Heinkel He 111 bombers during the Battle of Britain

Background

The early stages of World War II saw successful German invasions on the continent aided by the air power of the Luftwaffe, which was able to establish tactical air superiority with great efficiency. The speed with which German forces defeated most of the defending armies in Norway in early 1940 created a significant political crisis in Britain. In early May 1940, the Norway Debate questioned the fitness for office of British Prime Minister Neville Chamberlain. On May 10, the same day Winston Churchill became British Prime Minister, the Germans initiated the Battle of France with an aggressive invasion of French territory. RAF Fighter Command was desperately short of trained pilots and aircraft, but despite the objections of its commander Hugh Dowding that the diversion of his forces would leave home defenses weak, Churchill sent fighter squadrons to support operations in France, where the RAF suffered heavy losses.

After the evacuation of British and French soldiers from Dunkirk and the French surrender on June 22, 1940, Hitler mainly focused his energies on the possibility of invading the Soviet Union in the belief that the British, defeated on the continent and without European allies, would quickly come to terms. The Germans were so convinced of an imminent armistice that they began constructing street decorations for the homecoming parades of victorious troops. Although the British Foreign Secretary, Lord Halifax, and certain elements of the British public favored negotiated peace with an ascendant Germany, Churchill and a majority of his Cabinet refused to consider an armistice. Instead, Churchill used his skillful rhetoric to harden public opinion against capitulation and prepare the British for a long war. In his “This was their finest hour” speech of 18 June 1940, Churchill declared:

What General Weygand has called The Battle of France is over. The battle of Britain is about to begin. Upon this battle depends the survival of Christian civilisation. Upon it depends our own British life and the long continuity of our institutions and our Empire. The whole fury and might of the enemy must very soon be turned on us. Hitler knows that he will have to break us in this island or lose the war. If we can stand up to him, all Europe may be free and the life of the world may move forward into broad, sunlit uplands. But if we fail, then the whole world, including the United States, including all that we have known and cared for, will sink into the abyss of a new Dark Age made more sinister, and perhaps more protracted, by the lights of a perverted science. Let us therefore brace ourselves to our duties, and so bear ourselves that, if the British Empire and its Commonwealth last for a thousand years, men will still say, “This was their finest hour.”

From the outset of his rise to power, Hitler expressed admiration for Britain and throughout the Battle period he sought neutrality or a peace treaty. In secret conference on May 23, 1939 Hitler set out his rather contradictory strategy that an attack on Poland was essential and “will only be successful if the Western Powers keep out of it. If this is impossible, then it will be better to attack in the West and to settle Poland at the same time [with a surprise attack]. If Holland and Belgium are successfully occupied and held, and if France is also defeated, the fundamental conditions for a successful war against England will have been secured. England can then be blockaded from Western France at close quarters by the Air Force, while the Navy with its submarines extend the range of the blockade.”

The Blitz

The Blitz, from the German word “Blitzkrieg” (lightning war) was the name borrowed by the British press and applied to the heavy and frequent bombing raids carried out over Britain in 1940 and 1941 during the Second World War. This concentrated, direct bombing of industrial targets and civilian centers began with heavy raids on London on September 7, 1940, during the Battle of Britain. Adolf Hitler’s and Hermann Goering’s plans to destroy the Royal Air Force to allow an invasion of Britain were failing. In response to an RAF raid on Berlin, itself prompted by an accidental German bombing of London, they changed their tactics to the sustained bombing of civilian targets.

From September 7, 1940, one year into the war, London was systematically bombed by the Luftwaffe for 57 consecutive nights. More than one million London houses were destroyed or damaged and more than 40,000 civilians were killed, almost half of them in London. Ports and industrial centers outside London were also attacked. The main Atlantic sea port of Liverpool was bombed, causing nearly 4,000 deaths within the Merseyside area during the war. The North Sea port of Hull, a convenient and easily found target or secondary target for bombers unable to locate their primary targets, was subjected to 86 raids in the Hull Blitz during the war, with a conservative estimate of 1,200 civilians killed and 95 percent of its housing stock destroyed or damaged. Other ports, including Bristol, Cardiff, Portsmouth, Plymouth, Southampton, and Swansea, were also bombed, as were the industrial cities of Birmingham, Belfast, Coventry, Glasgow, Manchester, and Sheffield. Birmingham and Coventry were chosen because of the Spitfire and tank factories in Birmingham and the many munitions factories in Coventry. The city center of Coventry was almost destroyed, as was Coventry Cathedral.

The bombing failed to demoralize the British into surrender or significantly damage the war economy. The eight months of bombing never seriously hampered British production and the war industries continued to operate and expand. The Blitz was only authoried when the Luftwaffe failed to meet preconditions for a 1940 launch of Operation Sea Lion, the provisionally planned German invasion of Britain. By May 1941, the threat of an invasion of Britain had ended, and Hitler’s attention turned to Operation Barbarossa, the invasion of the Soviet Union. In comparison to the later Allied bombing campaign against Germany, the Blitz resulted in relatively few casualties; the British bombing of Hamburg in July 1943 inflicted some 42,000 civilian deaths, about the same as the entire Blitz.

The Blitz: Office workers make their way to work through debris after a heavy air raid by the German Luftwaffe.

Conflict in the Atlantic

The Battle of the Atlantic was the longest continuous military campaign in World War II, running from 1939 to the defeat of Germany in 1945. It focused on naval blockades and counter-blockades to prevent wartime supplies from reaching Britain or Germany.

The Battle of the Atlantic was the longest continuous military campaign in World War II, running from 1939 to the defeat of Germany in 1945. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany’s subsequent counter-blockade. This battle peaked from mid-1940 through to the end of 1943. The Battle of the Atlantic pitted U-boats and other warships of the Kriegsmarine (German navy) and aircraft of the Luftwaffe (German Air Force) against the Royal Canadian Navy, Royal Navy, United States Navy, and Allied merchant shipping. The convoys, mainly from North America and going to the United Kingdom and the Soviet Union, were primarily protected for the most part by the British and Canadian navies and air forces. These forces were aided by ships and aircraft of the United States from September 13, 1941. The Germans were joined by submarines of the Italian Royal Navy (Regia Marina) after their Axis ally Italy entered the war on June 10, 1940.

As an island nation, the United Kingdom was dependent on imported goods. Britain required more than a million tons of imported material per week in order to be able to survive and fight. In essence, the Battle of the Atlantic was a tonnage war: the Allied struggle to supply Britain and the Axis attempt to stem the flow of merchant shipping that enabled Britain to keep fighting. From 1942 on, the Germans sought to prevent the build-up of Allied supplies and equipment in the British Isles in preparation for the invasion of occupied Europe. The defeat of the U-boat threat was a prerequisite for pushing back the Germans. Winston Churchill later wrote,

The Battle of the Atlantic was the dominating factor all through the war. Never for one moment could we forget that everything happening elsewhere, on land, at sea or in the air depended ultimately on its outcome.— Winston ChurchillThe outcome of the battle was a strategic victory for the Allies—the German blockade failed—but at great cost: 3,500 merchant ships and 175 warships were sunk for the loss of 783 U-boats.

The name “Battle of the Atlantic” was coined by Winston Churchill in February 1941. It has been called the “longest, largest, and most complex” naval battle in history. It involved thousands of ships in more than 100 convoy battles and perhaps 1,000 single-ship encounters, in a theater covering thousands of square miles of ocean. The situation changed constantly, with one side or the other gaining advantage as participating countries surrendered, joined, and even changed sides, and as new weapons, tactics, counter-measures, and equipment were developed by both sides. The Allies gradually gained the upper hand, overcoming German surface raiders by the end of 1942 and defeating the U-boats by mid-1943, though losses due to U-boats continued until war’s end.

Battle of the Atlantic: Officers on the bridge of a destroyer, escorting a large convoy of ships  tokeep a sharp look out for attacking enemy submarines during the Battle of the Atlantic, October 1941.

Early Skirmishes

In 1939, the Kriegsmarine lacked the strength to challenge the combined British Royal Navy and French Navy for command of the sea. Instead, German naval strategy relied on commerce raiding using capital ships, armed merchant cruisers, submarines, and aircraft. Many German warships were already at sea when war was declared, including most of the available U-boats and the “pocket battleships” which sortied into the Atlantic in August. These ships immediately attacked British and French shipping. U-30 sank the ocean liner SS Athenia within hours of the declaration of war in breach of her orders not to sink passenger ships. The U-boat fleet which dominated so much of the Battle of the Atlantic was small at the beginning of the war; many of the 57 available U-boats were the small and short-range Type IIs, useful primarily for mine laying and operations in British coastal waters. Much of the early German anti-shipping activity involved mine laying by destroyers, aircraft, and U-boats off British ports.

With the outbreak of war, the British and French immediately began a blockade of Germany, although this had little immediate effect on German industry. The Royal Navy quickly introduced a convoy system for the protection of trade that gradually extended out from the British Isles, eventually reaching as far as Panama, Bombay, and Singapore. Convoys allowed the Royal Navy to concentrate its escorts near the one place the U-boats were guaranteed to be found, the convoys. Each convoy consisted of between 30 and 70 mostly unarmed merchant ships.

U-Boat Strategy

Early in the war, Dönitz submitted a memorandum to Grand Admiral Erich Raeder, the German navy’s Commander-in-Chief, in which he estimated effective submarine warfare could bring Britain to her knees because of her dependence on overseas commerce. He advocated a system known as the Rudeltaktik (the so-called “wolf pack”), in which U-boats would spread out in a long line across the projected course of a convoy. Upon sighting a target, they would come together to attack en masse and overwhelm any escorting warships. While escorts chased individual submarines, the rest of the “pack” would be able to attack the merchant ships with impunity. Dönitz calculated that 300 of the latest Atlantic Boats (the Type VII) would create enough havoc among Allied shipping that Britain would be knocked out of the war.

Some historians maintain that the German U-boat strategy came close to winning the Battle of the Atlantic, that the Allies were almost defeated, and that Britain was brought to the brink of starvation. Others, including Blair and Alan Levin, disagree.

The focus on U-boat successes, the “aces” and their scores, the convoys attacked, and the ships sunk, serves to camouflage the Kriegsmarine‘s manifold failures. In particular, this was because most of the ships sunk by U-boat were not in convoys, but sailing alone.

At no time during the campaign were supply lines to Britain interrupted; even during the Bismarck crisis, convoys sailed as usual (although with heavier escorts). In all, during the Atlantic Campaign only 10% of transatlantic convoys that sailed were attacked, and of those attacked only about 10%were lost. More than 99% of all ships sailing to and from the British Isles during World War II did so successfully.

Outcomes

The Germans failed to stop the flow of strategic supplies to Britain, resulting in the build-up of troops and supplies needed for the D-Day landings. The defeat of the U-boat was a necessary precursor for accumulation of Allied troops and supplies to ensure Germany’s defeat.

Victory was achieved at a huge cost: between 1939 and 1945, 3,500 Allied merchant ships (totaling 14.5 million gross tons) and 175 Allied warships were sunk and some 72,200 Allied naval and merchant seamen lost their lives. The Germans lost 783 U-boats and approximately 30,000 sailors killed, three-quarters of Germany’s 40,000-man U-boat fleet.

Operation Barbarossa

In June 1941, the German army launched an invasion of the Soviet Union, opening the largest land theater of war in history and trapping most of the Axis’ military forces in a war of attrition.

Operation Barbarossa was the code name for Nazi Germany’s World War II invasion of the Soviet Union, which began on June 22, 1941. The operation was driven by Adolf Hitler’s ideological desire to destroy the Soviet Union as outlined in his 1925 manifesto Mein Kampf.

Setting the Stage for the Invasion

In the two years leading up to the invasion, the two countries signed political and economic pacts for strategic purposes. Nevertheless, on December 18, 1940, Hitler authorized an invasion of the Soviet Union with a planned start date of May 15, 1941. The actual invasion began on June 22, 1941. Over the course of the operation, about four million Axis soldiers invaded the Soviet Union along a 1,800-mile front, the largest invasion force in the history of warfare. In addition to troops, the Germans employed some 600,000 motor vehicles and between 600,000 and 700,000 horses. It transformed the perception of the Soviet Union from aggressor to victim and marked the beginning of the rapid escalation of the war, both geographically and in the formation of the Allied coalition.

The Germans won resounding victories and occupied some of the most important economic areas of the Soviet Union, mainly in Ukraine, both inflicting and sustaining heavy casualties. Despite their successes, the German offensive stalled on the outskirts of Moscow and was subsequently pushed back by a Soviet counteroffensive. The Red Army repelled the Wehrmacht ‘s strongest blows and forced the unprepared Germany into a war of attrition. The Germans would never again mount a simultaneous offensive along the entire strategic Soviet-Axis front. The failure of the operation drove Hitler to demand further operations inside the USSR of increasingly limited scope that eventually failed, such as Case Blue and Operation Citadel.

The failure of Operation Barbarossa was a turning point in the fortunes of the Third Reich. Most importantly, the operation opened up the Eastern Front, to which more forces were committed than in any other theater of war in world history. The Eastern Front became the site of some of the largest battles, most horrific atrocities, and highest casualties for Soviets and Germans alike, all of which influenced the course of both World War II and the subsequent history of the 20th century. The German forces captured millions of Soviet prisoners of war who were not granted protections stipulated in the Geneva Conventions. A majority m never returned alive; Germany deliberately starved the prisoners to death as part of a “Hunger Plan” that aimed to reduce the population of Eastern Europe and then re-populate it with ethnic Germans. Over a million Soviet Jews were murdered by Einsatzgruppen death squads and gassing as part of the Holocaust.

Motivations for Invading USSR

As early as 1925, Adolf Hitler vaguely declared in his political manifesto and autobiography Mein Kampf that he would invade the Soviet Union, asserting that the German people needed to secure Lebensraum (“living space”) to ensure the survival of Germany for generations to come. On February 10, 1939, Hitler told his army commanders that the next war would be “purely a war of Weltanschauungen…totally a people’s war, a racial war.” On November 23, once World War II already started, Hitler declared that “racial war has broken out and this war shall determine who shall govern Europe, and with it, the world.” The racial policy of Nazi Germany viewed the Soviet Union (and all of Eastern Europe) as populated by non-Aryan Untermenschen (“sub-humans”), ruled by “Jewish Bolshevik conspirators.” Hitler claimed in Mein Kampf that Germany’s destiny was to “turn to the East” as it did “six hundred years ago.” Accordingly, it was stated Nazi policy to kill, deport, or enslave the majority of Russian and other Slavic populations and repopulate the land with Germanic peoples, under the Generalplan Ost (“General Plan for the East”). The Germans’ belief in their ethnic superiority is discernible in official German records and by pseudoscientific articles in German periodicals at the time, which covered topics such as “how to deal with alien populations.”

Overview of the Battles

The initial momentum of the German ground and air attack completely destroyed the Soviet organizational command and control within the first few hours, paralyzing every level of command from the infantry platoon to the Soviet High Command in Moscow. Therefore, Moscow failed to grasp the magnitude of the catastrophe that confronted the Soviet forces in the border area. Marshal Semyon Timoshenko called for a general counteroffensive on the entire front “without any regards for borders” that both men hoped would sweep the enemy from Soviet territory. Timoshenko’s order was not based on a realistic appraisal of the military situation at hand and resulted in devastating casualties.

Four weeks into the campaign, the Germans realized they had grossly underestimated Soviet strength. The German troops used their initial supplies without attaining the expected strategic freedom of movement. Operations were slowed to allow for resupply and adapt strategy to the new situation. Hitler had lost faith in battles of encirclement as large numbers of Soviet soldiers had escaped the pincers. He now believed he could defeat the Soviets by economic damage, depriving them of the industrial capacity to continue the war. That meant seizing the industrial center of Kharkov, the Donbass, and the oil fields of the Caucasus in the south and the speedy capture of Leningrad, a major center of military production, in the north.

After a German victory in Kiev, the Red Army no longer outnumbered the Germans and no more trained reserves were available. To defend Moscow, Stalin could field 800,000 men in 83 divisions, but no more than 25 divisions were fully effective. Operation Typhoon, the drive to Moscow, began on October 2. The Germans initially won several important battles, and the German government now publicly predicted the imminent capture of Moscow and convinced foreign correspondents of a pending Soviet collapse. On December 2, the German army advanced to within 15 miles of Moscow and could see the spires of the Kremlin, but by then the first blizzards had already begun. A reconnaissance battalion also managed to reach the town of Khimki, about 5 miles away from the Soviet capital. It captured the bridge over the Moscow-Volga Canal as well as the railway station, which marked the farthest eastern advance of German forces. But in spite of the progress made, the Wehrmacht was not equipped for winter warfare, and the bitter cold caused severe problems for their guns and equipment. Further, weather conditions grounded the Luftwaffe from conducting large-scale operations. Newly created Soviet units near Moscow now numbered over 500,000 men, and on December 5, they launched a massive counterattack as part of the Battle of Moscow that pushed the Germans back over 200 miles. By late December 1941, the Germans had lost the Battle for Moscow, and the invasion had cost the German army over 830,000 casualties in killed, wounded, captured, or missing in action.

Significance

Operation Barbarossa was the largest military operation in human history—more men, tanks, guns, and aircraft were committed than had ever been deployed before in a single offensive. Seventy-five percent of the entire German military participated. The invasion opened up the Eastern Front of World War II, the largest theater of war during that conflict, which witnessed titanic clashes of unprecedented violence and destruction for four years that resulted in the deaths of more than 26 million people. More people died fighting on the Eastern Front than in all other fighting across the globe during World War II. Damage to both the economy and landscape was enormous for the Soviets as approximately 1,710 towns and 70,000 villages were completely annihilated.

More than just ushering in untold death and devastation, Operation Barbarossa and the subsequent German failure to achieve their objectives changed the political landscape of Europe, dividing it into eastern and western blocs. The gaping political vacuum left in the eastern half of the continent was filled by the USSR when Stalin secured his territorial prizes of 1939–40 and firmly placed his Red Army in Bulgaria, Romania, Hungary, Poland, Czechoslovakia, and the eastern half of Germany. As a consequence, eastern Europe became Communist in political disposition and western Europe fell under the democratic sway of the United States, a nation uncertain about its future policies in Europe. Instead of profiting the German people, Operation Barbarossa’s failure instigated untold suffering when an estimated 1.4 million ethnic Germans died as a result of their forced flight from the East to the West, whether during the German retreat or later following the surrender.

Operation Barbarossa: Clockwise from top left: German soldiers advance through Northern Russia, German flamethrower team in the Soviet Union, Soviet planes flying over German positions near Moscow, Soviet prisoners of war on the way to German prison camps, Soviet soldiers fire at German positions.

The Holocaust

The German government led by Adolf Hitler and the Nazi Party was responsible for the Holocaust: the deliberate and systematic extermination of approximately six million Jews, 2.7 million ethnic Poles, and four million others who were deemed “unworthy of life.”

The Holocaust, also known as the Shoah (Hebrew for “the catastrophe”), was a genocide in which Adolf Hitler’s Nazi Germany and its collaborators killed approximately six million Jews. The victims included 1.5 million children and represented about two-thirds of the nine million Jews who resided in Europe. Some definitions of the Holocaust include the additional five million non-Jewish victims of Nazi mass murders, bringing the total to about 11 million. Killings took place throughout Nazi Germany, German-occupied territories, and territories held by allies of Nazi Germany.

The Plan for Genocide

From 1941 to 1945, Jews were systematically murdered in one of the deadliest genocides in history, part of a broader aggregate of acts of oppression and killings of various ethnic and political groups in Europe by the Nazi regime. Under the coordination of the SS and direction from the highest leadership of the Nazi Party, every arm of Germany’s bureaucracy was involved in the logistics and administration of the genocide. Other victims of Nazi crimes included ethnic Poles, Soviet citizens and Soviet POWs, other Slavs, Romanis, communists, homosexuals, Freemasons, Jehovah’s Witnesses, and the mentally and physically disabled. A network of about 42,500 facilities in Germany and German-occupied territories was used to concentrate victims for slave labor, mass murder, and other human rights abuses. Over 200,000 people were Holocaust perpetrators.

The persecution and genocide were carried out in stages, culminating in what Nazis termed the “Final Solution to the Jewish Question,” an agenda to exterminate Jews in Europe. Initially, the German government passed laws to exclude Jews from civil society, most prominently the Nuremberg Laws of 1935. Nazis established a network of concentration camps starting in 1933 and ghettos following the outbreak of World War II in 1939. In 1938, legal repression and resettlement turned to violence on Kristallnacht (“Night of Broken Glass”), when Jews were attacked and Jewish property was vandalized. Over 7,000 Jewish shops and more than 1,200 synagogues (roughly two-thirds of the synagogues in areas under German control) were damaged or destroyed. In 1941, as Germany conquered new territory in eastern Europe, specialized paramilitary units called Einsatzgruppen (“death squads”) murdered around two million Jews, partisans, and others, often in mass shootings. By the end of 1942, victims were regularly transported by freight trains to extermination camps where most who survived the journey were systematically killed in gas chambers. This continued until the end of World War II in Europe in April–May 1945.

Jewish armed resistance was limited. The most notable exception was the Warsaw Ghetto uprising of 1943, when thousands of poorly-armed Jewish fighters held the Waffen-SS at bay for four weeks. An estimated 20,000–30,000 Jewish partisans actively fought against the Nazis and their collaborators in Eastern Europe. French Jews took part in the French Resistance, which conducted a guerrilla campaign against the Nazis and Vichy French authorities. More than 100 armed Jewish uprisings took place.

Nuremberg Laws: Racial classification chart based on the Nuremberg Laws of 1935.

Distinguishing Features

All branches of Germany’s bureaucracy were engaged in the logistics that led to the genocides, turning the Third Reich into what one Holocaust scholar, Michael Berenbaum, has called “a genocidal state”:

Every arm of the country’s sophisticated bureaucracy was involved in the killing process. Parish churches and the Interior Ministry supplied birth records showing who was Jewish; the Post Office delivered the deportation and denaturalization orders; the Finance Ministry confiscated Jewish property; German firms fired Jewish workers and disenfranchised Jewish stockholders.

Saul Friedländer writes that: “Not one social group, not one religious community, not one scholarly institution or professional association in Germany and throughout Europe declared its solidarity with the Jews.” He writes that some Christian churches declared that converted Jews should be regarded as part of the flock, but only up to a point. Friedländer argues that this makes the Holocaust distinctive because antisemitic policies were able to unfold without the interference of countervailing forces normally found in advanced societies, such as industry, small businesses, churches, trade unions, and other vested interests and lobby groups.

In many other genocides, pragmatic considerations such as control of territory and resources were central to the genocide policy. The Holocaust, however, was driven almost entirely by ideology. Israeli historian and scholar Yehuda Bauer argues:

The basic motivation [of the Holocaust] was purely ideological, rooted in an illusionary world of Nazi imagination, where an international Jewish conspiracy to control the world was opposed to a parallel Aryan quest. No genocide to date had been based so completely on myths, on hallucinations, on abstract, nonpragmatic ideology—which was then executed by very rational, pragmatic means.

The use of extermination camps (also called “death camps”) equipped with gas chambers for the systematic mass extermination of peoples was an unprecedented feature of the Holocaust. These were established at Auschwitz, Belzec, Chełmno, Jasenovac, Majdanek, Maly Trostenets, Sobibór, and Treblinka. They were built for the systematic killing of millions, primarily by gassing but also by execution and extreme work under starvation conditions. Stationary facilities built for the purpose of mass extermination resulted from earlier Nazi experimentation with poison gas during the secret Action T4 euthanasia program against mental patients.  Rudolf Höss, the longest-serving commandant of Auschwitz concentration camp, said:

Another improvement we made over Treblinka was that we built our gas chambers to accommodate 2,000 people at one time, whereas at Treblinka their 10 gas chambers only accommodated 200 people each. The way we selected our victims was as follows: we had two SS doctors on duty at Auschwitz to examine the incoming transports of prisoners. The prisoners would be marched by one of the doctors who would make spot decisions as they walked by. Those who were fit for work were sent into the Camp. Others were sent immediately to the extermination plants. Children of tender years were invariably exterminated, since by reason of their youth they were unable to work. Still another improvement we made over Treblinka was that at Treblinka the victims almost always knew that they were to be exterminated and at Auschwitz we endeavored to fool the victims into thinking that they were to go through a delousing process. Of course, frequently they realized our true intentions and we sometimes had riots and difficulties due to that fact. Very frequently women would hide their children under the clothes but of course when we found them we would send the children in to be exterminated. We were required to carry out these exterminations in secrecy but of course the foul and nauseating stench from the continuous burning of bodies permeated the entire area and all of the people living in the surrounding communities knew that exterminations were going on at Auschwitz.

Auschwitz: Hungarian Jews being selected by Nazis to be sent to the gas chamber at Auschwitz concentration camp.