The decade known for both the Great Depression and World War II's most intense fighting is the 1930s and early 1940s. The economic turmoil of the Great Depression began with the stock market crash in 1929 and resulted in widespread unemployment and poverty. As nations struggled economically, the decade also saw the rise of totalitarian regimes, leading to the outbreak of World War II in 1939. The conflict escalated through the early 1940s, culminating in significant battles and shifts in global power dynamics, ultimately reshaping the political landscape and laying the groundwork for post-war recovery.