The document is a chapter from a history textbook covering the period from 1919 to 1939. It discusses the postwar instability and uncertainties in Europe following World War 1. It then describes how the Great Depression originated in the United States and spread worldwide, causing economic crises. Finally, it explains how fascist dictators like Mussolini and Hitler rose to power in Italy and Germany in response to the political and economic turmoil, and began aggressively invading and conquering other countries.