Albert Speer's testimony in the series is now considered highly unreliable. Speer considerably downplayed his involvement in Nazi atrocities. After his death a letter he wrote in December 1971 proved he had full knowledge of the Holocaust throughout its course, despite his repeated public denials.

The series was criticized for almost completely ignoring the Soviet invasions of Poland, Lithuania, Latvia, Estonia, Finland, Romania, Bessarabia and Bukovina in 1939-40.

The series was accused of downplaying the contribution of the various colonies of the British Empire to the war against Germany.

The attack on the US naval base at Pearl Harbor was regarded as a war crime as the Japanese government did not declare war first. Declarations of war were rendered obsolete after World War II by the United Nations Charter. The Japanese had sent a message stating that negotiations with the US had been terminated, but there was a delay in its translation and it arrived half an hour after the attack had started. Japan formally declared war on the United States and the British Empire on 8 December 1941 (7 December in US time).

Without the invasion of the Soviet Union on 22 June 1941, Germany would have run out of oil by August and would then have been unable to continue the war against the British Empire.

The joint German-Soviet invasion of Poland was agreed in the Molotov-Ribbentrop Pact on 23 August 1939. Adolf Hitler could only invade Poland if Joseph Stalin did as well, otherwise Germany risked fighting a two-front war in 1939 before it had sufficiently rearmed. Stalin waited until 17 September before launching his invasion, knowing France and the British Empire would be unable to declare war on the Soviet Union as well as Germany.

Some of the information, especially with regard to German-Soviet relations in 1939-41, is considered outdated due to the release of new material after the end of the Cold War.

The series was criticized for ignoring war crimes committed by the Allies, especially the Soviet Union.

Germany and the Soviet Union agreed to invade Poland in a secret protocol of the Molotov-Ribbentrop Pact, signed on 23 August 1939. In 1989 the Soviet government publicly apologized for the secret protocol.

Primetime Emmy Award Winner for Outstanding Documentary Achievements (Cultural) 1974, Jeremy Isaacs, Producer.

Adolf Hitler and Benito Mussolini's decision to declare war on the United States on 11 December 1941 is described in the series as a mistake. However it is likely that it made no difference. As the UK had declared war on Japan after the attack on Pearl Harbor, all restrictions on aiding Britain were off. It would only have been a short matter of time until German and Italian U-Boats began sinking American ships that were carrying arms and munitions to the UK, giving the US government its casus belli to declare war on Germany and Italy. Hitler and Mussolini could no longer ignore the vast amount of economic and military aid the US was giving to the Soviet Union and the British Empire. Some historians believe that Germany and Italy should have declared war on the US after the Destroyers for Bases Agreement in 1940. The US had officially abandoned its neutral stance in March 1941 with the beginning of Lend-Lease. American destroyers escorting convoys had already been de facto at war for months with German U-boats in the Atlantic, and Hitler's war declaration made the Second Happy Time possible for U-boats. Early in December 1941 Hitler and Mussolini had learned of "Rainbow Five", plans for offensive operations by American forces against Axis forces in Europe and North Africa. It is disputed whether they were aware of the Plan Dog memorandum, which determined the US would focus on defeating Germany and Italy while fighting a defensive war in the Pacific against Japan.

It was unknown when the series was made that the fascist Spanish dictator Francisco Franco had offered to join the Axis on 19 June 1940, but had demanded Cameroon for Spain, which was unacceptable to Hitler.

Poland helped Adolf Hitler overrun Czechoslovakia by invading the borderland and annexing Zaolzie in 1938. The Polish government devised the Madagascar Plan in 1937.

Despite the controversy over the attack on the US naval base at Pearl Harbor happening without a prior declaration of war, the British did not declare war when they invaded Iceland in 1940 and Iran in 1941.

Joseph Stalin deliberately waited until 17 September 1939 before launching his invasion of Poland, since he knew that the UK and France would not be able to declare war on the Soviet Union as well as Germany. The UK and France did consider declaring war following the Soviet invasion of Finland on 30 November 1939, as well as immediately bombing Baku to help the Finns.

Joseph Stalin intended to attack German forces in Eastern Europe by 1944. Adolf Hitler was aware of this and launched Operation Barbarossa on 22 June 1941 as a pre-emptive strike, before Stalin had time to fully prepare for war against the European Axis Powers. The Soviet offensive plans controversy suggested Stalin was preparing to attack the Axis in the summer of 1941.

The Soviets had already used mobile gas vans to kill people without trial during the Great Purge from 1936 to 1938.

Despite its name, the Neutrality Patrol greatly favored the British as the Royal Navy had far greater access to the Atlantic. While German naval shipping and military aircraft could operate only from the coast of Europe to intercept British ships, German ships could be intercepted by British military forces operating from the UK, Canada, Newfoundland, Labrador, Gibraltar, Sierra Leone, Gambia, Nigeria, South Africa, British Togoland, the British Cameroons, the Falkland Islands, South Georgia, Saint Helena, Ascension Island, Bermuda, Jamaica, Trinidad, Barbados, The Bahamas, the British Leeward Islands, the British Windward Islands, the British Virgin Islands, British Honduras, and British Guiana.

Many historians believe Japan surrendered because of the Soviet Union's declaration of war on 9 August 1945 and simultaneous invasion of Manchuria. It has also been suggested that an Allied naval blockade combined with conventional bombing would have been able to starve Japan into surrendering without the need for nuclear weapons.

Albert Speer was interviewed by Martin Smith, who strongly disliked the entire experience. Smith was disgusted that Speer seemed unashamed of his role in the Nazi regime, but he had to be polite in order for the interview to proceed. He still feels uncomfortable about the experience.

The UK and France rejected a German-Soviet peace proposal on 28 September 1939. Adolf Hitler offered to end the war on 6 October 1939 following the German-Soviet conquest of Poland. The German government put out peace feelers to Britain on 26 May 1940, the first day of the withdrawal of the British Expeditionary Force (BEF) from Dunkirk. Hitler offered to end the war with the UK on 19 July 1940 following the Fall of France, and only authorized the bombing of RAF fighter bases in August after the British had already bombed German cities for three months. In May 1941 he again offered to end the war in the West if the British Empire did not interfere with Operation Barbarossa. Winston Churchill chose to reject Hitler's peace offers in 1940 and 1941.

Although the invasion of the Soviet Union is often portrayed as a mistake and a turning point in the war, in reality Adolf Hitler could not continue the war against the British Empire without vastly increased reserves of oil and grain. He was forced to turn east after the failure to defeat the UK in 1940-41, in order to seize the natural resources.

Not mentioned in the series is the fact that Joseph Stalin violated the Molotov-Ribbentrop Pact by annexing Bukovina on 28 June 1940. Following this the German High Command began planning the invasion of the Soviet Union in July 1940 under the code name Operation Otto, which was later changed to Operation Barbarossa.

While much is said of Stalingrad being of symbolic value for Hitler, it was a transit hub for oil deliveries for the Soviets, who got their oil from Chechnya and Azerbaijan at the time. The whole southern focus of the Axis campaign on the Eastern Front was to capture the Caucasus oilfields.

People in the UK were not told that the RAF began bombing German cities on 15 May 1940, after the RAF had already bombed Dortmund on 10 May and Monchengladbach on 11 May.

The Battle of Greece did not in fact delay the invasion of the Soviet Union. The operation could not begin until June 1941 because of equipment shortages, a delay in building aircraft bases in eastern Europe, and because the rivers and canals were heavily flooded, making it impossible for armored units to move.

The series is often criticized as too Anglocentric.

When Joseph Stalin offered to formally join the Axis Powers on 25 November 1940 he also requested that Axis forces should withdraw from eastern Europe. This threatened to cut off Germany's main supply of oil from Romania, and led Adolf Hitler to authorize planning for Operation Barbarossa on 18 December 1940.

Early in 1941 Adolf Hitler was faced with the choice between obtaining more oil from the Soviet Union or surrendering. Undoubtedly Joseph Stalin would have resisted any demands for increased oil deliveries, or at least made an increase dependent on greatly increased German deliveries of manufactured products that Germany would have been incapable of meeting. Viewed in that light, the invasion of the Soviet Union appears inevitable, even without the ideological aspect.

Some historians have suggested there was no need for an invasion of Japan (Operation Downfall), and a naval blockade with conventional bombings would have starved Japan into surrendering. It is believed Operation Starvation would have forced the country to surrender in the summer of 1945 if it had been started earlier.

The United States did not declare war on Japan when it sent forces including the Flying Tigers to China.

The title "Operation Barbarossa" is often used for the Axis invasion of the Soviet Union. However it originally only referred to the Axis attack on Soviet-occupied eastern Poland on 22 June 1941.

The British government had plans to bomb the Soviet Union during 1940-41, due to the German-Soviet Commercial Agreement. Having consolidated Britain's control of Syria and Lebanon, Winston Churchill seriously considered using the RAF in Iraq to bomb the oilfields in Baku on 12 June 1941, just ten days before the European Axis Powers invaded the Soviet Union.

Some critics felt the series downplayed the extent to which the UK and France were occupying half the world by force in 1939.

The Battle of Midway was heralded as a turning point in the Pacific theater. However modern historians have asserted the battle made little difference, as Japan did not have the resources and the industrial or economic capacity to simultaneously fight the United States, China and the British Empire. The Guadalcanal Campaign has also been called a turning point.

Susan McConachy was responsible for locating ex-members of the SS for potential interviews. She spent months trying to find Karl Wolff, without success. However, whilst she was staying at a hotel in Berlin, Wolff arrived and introduced himself to her by saying, "I hear you are looking for me?" At first she was surprised by how charming he was, but as he tried to justify the ideology of Aryan superiority, she came to detest him. However, she did not argue with what he said, in order to gain his trust for an interview. She was unhappy with interviewing other SS veterans too, as she had to be dishonest about her own feelings and hoped that she didn't appear to totally agree with what they said.

The Royal Navy's blockade of Germany in both world wars was widely regarded as illegal under international law as it violated the Hague Convention of 1907. Admiral Erich Raeder said Germany's unrestricted submarine warfare was in response to the illegal naval blockade.

Germany invaded Denmark and Norway in April 1940 as a preventive manoeuvre against a planned, and openly discussed, Franco-British occupation of Norway entitled Plan R 4.

The Blitz happened because the British began bombing German cities on 10 May 1940. By late August 1940 Adolf Hitler was under immense pressure from his military commanders and from public opinion with Germany to retaliate.