In 1938, Nazi Germany annexed Austria and part of Czechoslovakia, and in 1939, Nazi Germany and the USSR concluded a pact to occupy the countries that lie between them; the USSR occupied Finland, Estonia, Latvia, and Lithuania, and Germany and the USSR split Poland in two. The occupation of Poland started World War II. Germany attacked the USSR in 1941. The USSR allied with the UK and USA, and emerged as one of the victors of the war, occupying most of central and eastern Europe.