Answer:
A part of a ideology used by the Nazis and Hitler.
Hitler thought that he should increase the amount of Aryan people in his world, so he would need to take over large chunks of land that are filled with such people, like Austria and the Sudentenland, the allies (UK and France) were favoring appeasement, because they were still sort of reeling from the first world war and would like to avoid a conflict if at all possible. Leading to the Munich conference. The Germans then wanted to take more land, ie. (Poland and possibly the USSR) so they invaded Poland, which caused WW2 to break out.