The Second World War (WW2) (1 September 1939 September 2, 1945) - War of the two world military-political coalitions, which became the largest armed conflict in history. It was attended by 62 of the 73 States that existed at the time (80% of the world population). Battles were fought on the territory of three continents and in the waters of the four oceans. This is the only conflict in which it was to use nuclear weapons.