Causes of World War IIThe causes of World War II have been given considerable attention by historians. The immediate precipitating event was the invasion of Poland by Nazi Germany on September 1, 1939, and the subsequent declarations of war on Germany made by Britain and France, but many other prior events have been suggested as ultimate causes.
Interwar periodIn the history of the 20th century, the interwar period (or interbellum) lasted from 11November 1918 to 1September 1939 (20years, 9months, 21 days)the end of the First World War to the beginning of the Second World War. The interwar period was relatively short, yet featured many significant social, political, and economic changes throughout the world. Petroleum-based energy production and associated mechanisation led to the prosperous Roaring Twenties, a time of both social mobility and economic mobility for the middle class.
International relations (1919–1939)International relations (1919–1939) covers the main interactions shaping world history in this era, known as the interwar period, with emphasis on diplomacy and economic relations. The coverage here follows the diplomatic history of World War I and precedes the diplomatic history of World War II.
Great DepressionThe Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagion began around September 1929 and led to the Wall Street stock market crash of October 24 (Black Thursday). It was the longest, deepest, and most widespread depression of the 20th century. Between 1929 and 1932, worldwide gross domestic product (GDP) fell by an estimated 15%.