Second World War,1939-9 On September 1,1939,German tanks and planes launched a full-scale blitzkrieg invasion of Poland.Two days later,Britain and France declared war against Germany, soon afterward,they were also at war with the Axis allies,Italy and Japan.The Second World War explodedSecond World War World War, 1939-9 • On September 1, 1939, German tanks and planes launched a full–scale blitzkrieg invasion of Poland. Two days later, Britain and France declared war against Germany, soon afterward, they were also at war with the Axis allies, Italy and Japan. The Second World War exploded