In 1938, the year before the outbreak of the Second world War, the countries with the largest populations were China, the Soviet Union, and the United States, although the United Kingdom had the largest overall population when it's colonies, dominions, and metropole are combined. Alongside France, these were the five Allied "Great Powers" that emerged victorious from the Second World War. The Axis Powers in the war were led by Germany and Japan in their respective theaters, and their smaller populations were decisive factors in their defeat. Manpower as a resource In the context of the Second World War, a country or territory's population played a vital role in its ability to wage war on such a large scale. Not only were armies able to call upon their people to fight in the war and replenish their forces, but war economies were also dependent on their workforce being able to meet the agricultural, manufacturing, and logistical demands of the war. For the Axis powers, invasions and the annexation of territories were often motivated by the fact that it granted access to valuable resources that would further their own war effort - millions of people living in occupied territories were then forced to gather these resources, or forcibly transported to work in manufacturing in other Axis territories. Similarly, colonial powers were able to use resources taken from their territories to supply their armies, however this often had devastating consequences for the regions from which food was redirected, contributing to numerous food shortages and famines across Africa, Asia, and Europe. Men from annexed or colonized territories were also used in the armies of the war's Great Powers, and in the Axis armies especially. This meant that soldiers often fought alongside their former-enemies. Aftermath The Second World War was the costliest in human history, resulting in the deaths of between 70 and 85 million people. Due to the turmoil and destruction of the war, accurate records for death tolls generally do not exist, therefore pre-war populations (in combination with other statistics), are used to estimate death tolls. The Soviet Union is believed to have lost the largest amount of people during the war, suffering approximately 24 million fatalities by 1945, followed by China at around 20 million people. The Soviet death toll is equal to approximately 14 percent of its pre-war population - the countries with the highest relative death tolls in the war are found in Eastern Europe, due to the intensity of the conflict and the systematic genocide committed in the region during the war.

At the beginning of the 19th century, the area of modern-day Italy, at the time a collection of various states and kingdoms, was estimated to have a population of nineteen million, a figure which would grow steadily throughout the century, and by the establishment of the Kingdom of Italy in 1861, the population would rise to just over 26 million.

Italy’s population would see its first major disruption during the First World War, as Italy would join the Allied Forces in their fight against Austria-Hungary and Germany. In the First World War, Italy’s population would largely stagnate at 36 million, only climbing again following the end of the war in 1920. While Italy would also play a prominent role in the Second World War, as the National Fascist Party-led country would fight alongside Germany against the Allies, Italian fatalities from the war would not represent a significant percentage of Italy’s population compared to other European countries in the conflict. As a result, Italy would exit the Second World War with a population of just over 45 million.

From this point onwards the Italian economy started to recover from the war, and eventually boomed, leading to increased employment and standards of living, which facilitated steady population growth until the mid-1980s, when falling fertility and birth rates would cause growth to largely cease. From this point onward, the Italian population would remain at just over 57 million, until the 2000s when it began growing again due to an influx of migrants, peaking in 2017 at just over 60 million people. In the late 2010s, however, the Italian population began declining again, as immigration slowed and the economy weakened. As a result, in 2020, Italy is estimated to have fallen to a population of 59 million.

During the Second World War, the three Axis powers of Germany, Italy, and Finland mobilized the largest share of their male population. For the Allies, the Soviet Union mobilized the largest share of men, as well as the largest total army of any country, but it was restricted in its ability to mobilize more due to the impact this would have on its economy. Other notable statistics come from the British Empire, where a larger share of men were drafted from Dominions than from the metropole, and there is also a discrepancy between the share of the black and white populations from South Africa.

However, it should be noted that there were many external factors from the war that influenced these figures. For example, gender ratios among the adult populations of many European countries was already skewed due to previous conflicts of the 20th century (namely WWI and the Russian Revolution), whereas the share of the male population eligible to fight in many Asian and African countries was lower than more demographically developed societies, as high child mortality rates meant that the average age of the population was much lower.

Albania, then known as Rumelia, was a province of the Ottoman Empire from the fifteenth century until it declared it's independence in 1912. Following a series of unsuccessful uprisings and brief occupations from nearby Serbia and Greece, Albania finally claimed its independence on November 28, 1912; however the Conference of London in 1913 then set the borders of the former-Ottoman states in Southern Europe, which left many ethnic Albanians living in other neighboring states, particularly Serbia (and what is now Kosovo). The newly-formed Albanian state collapsed in the wake of the First World War, and was controlled in parts by Greece, Italy and Serbia. The Paris Conference then established an independent Albanian state, which led to a period of political and economic turmoil that lasted until Italy's annexation of the region in 1939, during the Second World War. It is estimated that just under 3 percent of Albania's population perished as a direct result of the war, as Albania became the main theater for the Axis Powers' war against Greece. Italy then surrendered control of the area to Germany in 1943, and after the war ended in 1945, Albania became a Yugoslav satellite state and remained behind the Iron Curtain until it's collapse in the 1990s. Steady growth during the communist era From the war's end onwards, Albania's population enjoyed steady growth and almost tripled by 1990. Throughout this time, Albania underwent a series of political allegiances; first as a Yugoslav and then Soviet satellite states, but then became an important actor in the Sino-Soviet split, eventually siding with China in the 1960s. Gradually, Albania transitioned into a more isolationist and independent country in in the 1970s, and slowly adopted some more democratic practices. The total population surpassed two million people in the late 1960s, and three million in the late 1980s, but then a dramatic change in population growth occurred in the 1990s, as communism in Europe came to an end. Immediate decline following communism's end Increased freedom of movement, improved access to contraception and major lifestyle changes caused the population to fall into decline. The population did increase in the late 90s, despite a civil war in the first half of 1997 (in which over 2 thousand people died) sparked by a failure of the financial system in Albania. The Albanian Army was also involved in the war in neighboring Kosovo between 1998 and 1999. The 2000s brought about further decline, and the population is just 2.9 million in 2020, a decline of approximately 400,000 people in thirty years. Albania has been a candidate for accession to the EU since 2014, and membership would bring further change to the country.

Throughout history, the displacement and migration of Jewish populations has been a repeating theme. In ancient times, the worlds Jewish population was concentrated in the Middle East, especially around Judaism's spiritual homeland in present-day Israel. However, the population distribution of the world's Jewry began to shift in the Middle Ages, with an increasing share living in Europe. Initially, Western Europe (particularly France, Italy, and Spain) had the largest Jewish populations, before they then migrated eastward in later centuries. Between the 18th and mid-20th centuries, over half of the worl'd Jews lived in Europe, with over 80 percent of these living in Eastern Europe.

Poland had become a refuge for Jews fleeing persecution in the Middle Ages, although shifting borders and foreign influence meant that long-term security was never fully attained, and a series of pogroms in the Russian Empire in the 1800s, and rising anti-Semitism in Central Europe in the early-1900s contributred to waves of migration to the United States and Israel during this time. After the Holocaust saw the genocide of up to six million Jews (over one third of the world's Jewish population), the share of Jews living in Europe dropped drastically, and emmigration outside of Europe increased. Today, the United States has the world's largest Jewish population in the world at around 7.3 million people, just ahead of Israel with 7.1 million.

By mid-1941, Axis forces had already taken control of most of mainland Europe, as well as much of Northern Africa and parts of the Middle East*. At the outbreak of Operation Barbarossa, the major European countries not under Axis control were the officially-neutral states of Ireland, Portugal, Spain, Sweden, Switzerland, and Turkey, while the Soviet Union and United Kingdom were actively at war with the Axis Powers. By mid-1941, Germany and its allies controlled an area of approximately 3.28 million square kilometers in Europe; by comparison, modern Germany covers an area of approximately 357 thousand square kilometers. Axis control of Europe From September 1938, when Germany annexed the Czech Sudetenland, until June 1941, when Germany launched its invasion of the Soviet Union, the Axis Powers spent much of their time and resources consolidating power across Europe. Countries such as Bulgaria, Hungary, Romania, and Finland aligned themselves with Germany, as did Italy, who became one of the chief aggressors around the Mediterranean and in Africa. Germany and the Soviet Union both invaded and partitioned Poland in September 1939, through the Molotov-Ribbentrop Pact of non-aggression to one-another. Germany then took Denmark and most of Norway in April 1940, before pushing into Benelux and France in May. Italy also annexed Albania in April, which was used as a launching point for its failed invasion of Greece later in the year. As Italy had failed to secure the Balkans, a joint Axis offensive then pushed into Yugoslavia and Greece in April 1941, ultimately overwhelming any resistance. However, German intervention in the south then delayed the Axis invasion of the Soviet Union by over a month; Hitler later claimed that this was the reason for Germany's failure to take Moscow before the winter months, although many historians disagree. Launch of Operation Barbarossa Germany broke their pact of non-aggression with the Soviet Union with a surprise invasion, known as Operation Barbarossa, on June 22, 1941. While Axis forces had already extended control over most of Europe by this point, Operation Barbarossa became the largest military invasion or operation in human history. When compared with German capacities in its pre-1938 borders, within a few months of the invasion, the area of land controlled by Germany had grown by a factor of six, the population by a factor of four, and its access to natural resources and energy had also grown several times larger. These increased capacities were essential in allowing Germany to continue its expansion and aggression for the years to come, before the Soviet Union and the Western Allies eventually defeated the Axis forces four years later.

In Western Europe in the early twentieth century, the rate of car ownership increased rapidly, while ownership across the south and east was significantly lower. Between the First and Second World Wars, the number of cars in the eight largest Western European economies rose from just nine per 1,000 inhabitants in 1914 to 217 per 1,000 inhabitants in 1939. In six select countries across the south and east of Europe, these figures rose from just one to 17. There was a slight decrease in the number of cars over the 1940s due to the impact of the Second World War.