Definitely
Weather and size of Russia
because of colonial aspirations of germany
Germany's aggression toward Poland
Germany's unrestricted submarine warfare
The weather is nearly very hot.
Failed due to severe weather conditions
Germany's unrestricted submarine warfare
In September 1939, Germany and Slovakia invaded Poland. This lead to many countries declaring war.
Post-war Germany was at the mercy of so many different forces and factors.
Germany's aggression toward Poland
The Russians would be slow in getting their troops ready.
Stalin became his allie