World war: Understanding world war history—especially

Understanding world war history—especially World War I, World War II, and the speculation about World War III—is essential to protect global peace. World War I and II deeply affected political systems, economies, and societies. Introduction to World War II (1939–1945) World War II (1939–1945) was the deadliest, most costly, most widespread war in human history. The war saw the decline of the European colonial powers that had dominated global politics for the previous four centuries and the rise of the United States and the Soviet Union as superpowers. Tremendous advances in science, medicine, and military technology were made over the course of the conflict—from antibiotics to the atomic bomb —and ... World War II[b] or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Allies and the Axis. Nearly all of the world 's countries participated, with many nations mobilising all resources in pursuit of total war . Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war . World War II is the deadliest conflict in history, causing the death of 70 to ... Our world has been shaped by two all-consuming conflicts - and by a global superpower stand-off that brought the world to the brink of destruction. Explore the in-depth sections below.