The Germans wanted to take over countries smaller than them. Germany also wanted to take over the Jews. It all started in 1939 and ended in 1945.
Adolf Hitler wanted the German race to be the most powerful race in the world. The reason is so Germans could be the dominant race. He also hated the Jews, he tried to kill them all in concentration camps.
The British and French decided to declare war on Germany because of they took over Poland,Denmark,and Norway. Germany wanted all the Jews to be captured and killed in concentration camps, that way the German race would be the dominate race.
In 1945 the war ended and Germany lost,and Europe got back the land Germany took and everything was back to normal.

everything was found on www.ushmm.org