The Nuremberg Laws were passed in 1935 at the annual rally of the Nazi Party in Nuremberg. The Laws made it illegal for “Germans” to marry Jewish people and stated that only ethnic Germans, or those of similar status, could be citizens of the Third Reich. This deliberately ostracized Germany’s large Jewish population and revoked the citizenship of millions of Jewish people. Many Jews fled in the intervening years between the Nuremberg Laws and the implementation of the “Final Solution,” but many others did not or, rather, could not.

The Nuremberg Trials were a series of court proceedings held in the aftermath of World War II in which many Nazi leaders were tried for war crimes.

The Bolsheviks were trying to affect a communist revolution, which logically suggests they would have the support of industrial workers who, in theory, stood to benefit from a socialist takeover. A great deal of Bolshevik rhetoric and propaganda was directed, quite straightforwardly, at "the workers." The Allied Powers of World War I were determined to prevent a socialist uprising in Russia and committed small numbers of troops (comparably small) on the side of the “White Russians.” Rural workers and the landed aristocracy feared for their positions and their lives under a socialist regime. These fears would prove prescient in the coming years.

The Spanish Civil War erupted in 1936 when a group of generals rebelled against the democratically elected left-wing government. The War was fought between the Fascist forces of General Franco and the mostly guerilla forces of Republicanism. Franco and the military won by 1939, and a Fascist government was established until Franco’s death in 1975. During the Civil War, Franco received support from the Fascist governments of Hitler and Mussolini.

The Great Depression, which began in the United States in 1929, spread rapidly around the capitalist nations of Europe. The rise of Communism in Germany unnerved many of the traditional centers of power and a coalition formed to elect the Nazi Party so as to prevent the election of the Communist Party. During the economic depression of the 1930s, extremist parties on both ends of the political spectrum gained support.

The “March on Rome” was a popular movement in support of Mussolini and Fascism. It caused the collapse of the Italian government. King Victor Emmanuel III granted Mussolini dictatorial powers for a year. Once made dictator, Mussolini was able to pass laws that ensured his continued control of the Italian state long after his year appointment had finished.

In the years following World War I (and World War II), the British Empire gradually lost the vast majority of its territory to independence movements. The Statute of Westminster, passed in 1931, sought to legally codify the independence of the Commonwealth nations (like Canada and Australia) and define their relationship with the British Crown moving forward. The Statute afforded the Dominions legislative independence, but also ratified their connection to the Crown, requiring all Commonwealth nations to seek each other's approval before making any changes that would affect the monarchical line of succession.

During the second half of the nineteenth century and the early years of the twentieth century, millions of people from Europe immigrated to the United States to make a new life for themselves. Italians, Irish, and Germans were the most common immigrants. This all changed, however, when the United States started implementing quotas on the number of people who could emigrate from various countries. These laws favored Northern Europeans (who the American government believed to be more industrious and less likely to commit crime) over Southern and Eastern Europeans.

During the 1930s, France, like much of the rest of the world, was mired in its worst-ever economic depression. This increased class tensions and further polarized the political spectrum. Fascism became very popular in France, as it seemed to promise an end to corporate and political corruption. The "Popular Front" (an alliance of Republicans, Communists, and others) was created with the specific intent of combatting the rise of Fascism in France.

The emancipation of the serfs in the 1860s did not create the independent peasant class that one might theoretically assume it would. The freed peasants were burdened with extreme debts intended to compensate the aristocracy for their losses. This meant that they were serfs in all but name. Following the aborted revolutions of 1905, the debt was forgiven and a wealthy peasant class emerged in Russia for the first time. These “kulaks” gained land and wealth in a very short time, but also gained the ire of their contemporaries who were less wealthy and, more relevantly, they gained the disdain of Josef Stalin and the Communist Party. "Duma" was the name of the legislative assembly in pre-revolution Russia. "Gulags" was the name of the organization that ran Soviet enforced labor camps (and, later, a colloquial name for the camps themselves). "Boyars" were a class of feudal aristocrats from earlier periods in Russia's history.

By the time the Second World War began the working and middle classes enjoyed similar rights and after the war those rights were generally maintained or extended (in Western Europe anyway). What is certainly true is that after World War II class distinctions became far less rigid across European society than they were before. Ability and natural intelligence became more important than family background, and educational opportunities were extended to a wide spectrum of society. While social class inequalities certainly persisted (and continue to persist) in European countries, relative to the rigid class hierarchies of the preceding centuries the distinctions became more subtle.