Germany had lost ww1 which had many repercussions for the country the were force to accept responsibility for all of the allied forces money spent in the war which made Germany quickly fall into a depression. After this hitler rose to power on the promise to make Germany great again. What officially started ww2 was Germanies unprovoked attack on Poland after this the same thing that happened in ww1 happened in ww2 all of Poland’s allies came to their aid which brought in all of Germanies allies which resulted in a world war