The migration of peoples in the twentieth century affected European society and the nature of many European communities. The Soviet communists' forcible expulsion of Russian peasants and the Nazis' deportation and death of European Jews were just two of the most dramatic manifestations of this trend.

The Second World War and the accompanying economic restructuring of the continent resulted in even more widespread migrations. The most prominent pattern in this population mobility was the continued shift from the rural to the metropolis. Except for Albania, every European country now has at least one-third of its people living in a metropolitan city. Cities account for over 75% of the population in Western Europe.

Other large-scale forced migrations of peoples by governments, on the other hand, received little attention during the Cold War.

Millions of Germans, Hungarians, Poles, Ukrainians, Bulgarians, Serbs, Finns, Chechens, Armenians, Greeks, Turks, Balts, and Bosnian Muslims were moved during the century.

Parts of Europe were altered as a result of these forced displacements. Stalin physically relocated whole nations within the Soviet Union, killing millions of people in the process. The Nazis initially relocated Jews before attempting to exterminate them.

Cities in Eastern Europe that previously had big Jewish populations and a thriving Jewish religious and cultural life lost their Jewish identity. The return of Germans from Eastern Europe to Germany soon after World War II changed cities that had previously been German into virtually entirely inhabited areas. World War II generated a massive refugee crisis. An estimated 46 million individuals were affected.

World War II generated a massive refugee crisis. Between 1938 and 1948, an estimated 46 million people were moved in Central and Eastern Europe and the Soviet Union alone. Many cities in Germany, Central and Eastern Europe, and the Balkans had been devastated or conquered by invading troops. Hundreds of thousands of foreign immigrants were brought into Germany as slave labour by the Nazis.

Millions more were imprisoned as a result of the conflict. Some of these individuals returned willingly to their homeland; others, mainly Soviet captives afraid of being killed by Stalin, were compelled to return, and many were executed. Hundreds of thousands of captives from the Baltic, Poland, and Yugoslavia sought sanctuary in Western Europe.

Many individuals were displaced as a result of changes in political borders following the conflict.

For example, Poland, Czechoslovakia, and Hungary forcefully relocated millions of ethnic Germans to Germany.

This relocation of more than 12 million Germans effectively "fixed" the problem of German minorities residing outside of Germany's national borders, which had been one of Hitler's justifications for war against neighboring nations.

In another incidence of forced migration, hundreds of thousands of Poles were transported from territory acquired by the Soviet Union to inside Poland's new borders.

Other ethnic minorities, such as Ukrainians in Poland and Italians on the Yugoslav coast, were forced to return to their respective homelands. According to one historian, "war, brutality, and immense social dislocation made Versailles's ideal of national homogeneity a reality."

Over the last quarter-century, Europe's population, as measured by the European birthrate, has stabilized in a way that has alarmed many observers. Europeans have so few offspring that they can no longer replace themselves. Whereas European women produced 2.1 children on average in the 1950s, that rate decreased to 1.9 in the 1980s and is now at 1.4, which is below the replacement level.

The rate is significantly lower in Mediterranean nations such as Greece, Spain, and Italy. This situation contrasts sharply with the population expansion in the United States during the last decade, when the birthrate was about 2.1. If present rates persist, the United States will be debt-free by the middle of the century.

If current trends continue, the United States will have more people than Europe for the first time in history by the middle of the century.

There is no agreement on why the European birthrate has fallen. One frequently claimed cause is that women are deferring childbirth until later in their reproductive years. Nonetheless, governments have been attempting to curb immigration into Europe in reaction to public sentiment at a time when the continent may require more labor.

Because of the declining birthrate, Europe will confront the possibility of an elderly population.

The youthful vigour and drive that youth may give may move to the other side of the Atlantic. Economic innovation is unlikely to be stimulated by an aging population. The interior structure

The internal European market, which is currently larger than the internal American market, will contract. In contrast to the late nineteenth century (see Chapter 23), Europe will have fewer Europeans, and Europe's proportion of the global population will likewise decrease. Part of Europe's impact on the world in the nineteenth and early twentieth centuries was simply due to its population numbers.