World War II (1939-1945)

World War II, spanning from 1939 to 1945, was the deadliest international conflict in history. It reshaped global power structures, leading to the decline of European empires and the rise of the United States and Soviet Union as superpowers. The war accelerated technological and medical advances but also included atrocities like the Holocaust. Its conclusion with the use of atomic weapons initiated the Cold War and led to the establishment of the United Nations, defining the modern world order.