In early 1930s Adolf Hitler took as the leader of Germany. The Germany under him took fallowing aggressive actions :
1: He defied Versailles treaty by announcing the reintroduction of conscription in 1935.
2: He invaded and captured Rhineland (in western Germany) in 1936.
3: In 1938 Germany annexed Austria and later invaded Czechoslovakia.
4: On sept. 1939 Germany invaded Poland.