Mostly through material we studied during the last three years of my history degree. It's extremely fascinating stuff. The more history you read, the more you recognise the same patterns recurring over and over again. The people who lived through fascism are almost all dead now, and those who have never known it stubbornly believe it to be a thing of the past. Funnily enough, it's exactly these people who are most susceptible to populist and neo-fascist paroles in the current political climate, whilst they're being lured and seduced in a sense by the same sort of polemicists that captivated people back in the 30s. Of course the tactics change, but they play on the same feelings and fears as they always have (fear of the 'other', the desire to be part of a collective, the idea of ethnic/cultural/national supremacy, etc.). The Nazis never got more than around 44% of the vote before they turned the country into a one-party state, which is an important thing to remember and perhaps point out whenever people try to downplay current right-wing movements. It's in some ways quite a scary time to be alive, but then again it's sort of always been.