What events led to the start of WWII in both Europe and Asia?

Europe: The primary events which led to the outbreak of World War II in Europe were German aggressive expansionary policies in Eastern Europe, primarily the invasion of Poland, which triggered the outbreak.

Asia: The Soviet Union followed with a brief invasion of China in 1934, an event that drove Japan to ... World War II in Asia was preceded by a period of expansion by the militarist regime in Japan. Japanese expansion began in China with the invasion and occupation of Manchuria in 1931.