The 20th century, unlike any other century before it, witnessed dramatic changes in many areas such as science, technology, politics, religion and society. One of the most important and certainly the most obvious changes is the increasingly perilous nature of war. Certainly, people died in wars from the beginning, but in the 20th century, wars began to generate much higher death tolls, both among the armies in conflict and among civilian populations, the latter being the most significant change. more radical in terms of number of victims. Likewise, in the 20th century, two opposing dictatorships emerged. Although the two have many similarities, they represent the culmination of two different political ideologies that flourished in Europe since the mid-19th century. This all dates back to World War I, which produced a disillusioned public who increasingly sought to change their life circumstances, but attempted to do so outside of the established system. The two regimes are simply the two exact extremes that were produced by this reaction. National socialism represents an ultra-conservatism that goes well beyond the boundaries of conservatism as we know it today, while communism represents ultra-liberalism. Because these two were ideologically extreme on the right and left of the political spectrum respectively, in fact, they were actually completely wound up, so to speak, so that they were actually not that far apart from each other. the other ideologically after all. So the question is: if the ideology of the two regimes was so different, why were there so many similarities? What really linked them was the rejection of the same dominant doctrine: liberalism (Overy 639). Both of them preached against the bourgeoisie and praised the common...... middle of paper ...... and a similar event would happen in the future. It is important to consider them as archetypal examples of repression born of paranoia and ideologies transformed into bizarre shadows of their previous intentions. Although they are the two most studied and famous, there are other diets throughout world history that can be approached in a similar way. For example, in terms of ideology, a historian might approach communist China or, in terms of genocide, one might approach the Khmer Rouge regime in Cambodia using knowledge gleaned from the study of National Socialism and Communism. Likewise, it might be possible to use this same knowledge to predict when a country might move toward such a regime and try to prevent it. In this way, the legacy of these regimes is not one of terror and bloodshed, but rather a contribution to preventing further bloodshed...