The German-Soviet Non-Aggression Pact
While it might seem like Nazi Germany fought as a lone wolf, the country had actually singed a non-aggression pact with Russia before WWII started. This required both not to attack each other at any point in the coming decade.

The German Soviet Non Aggression Pact
Hitler wanted to use the pact to get into Poland with no roadblocks. While many thought Stalin would strike first, Hitler broke that back with the invasion of the Soviet Union in 1941. Russia immediately joined forces with the Allies, and pictured here is a Russian and American soldier working together.
The Umbrella Effect
Many soldiers used umbrellas to protect themselves from torrential downpours in WWII. Major Allison Digby Tatham-Warter always carried one with him into battle, albeit for reasons other than what you might think.

The Umbrella Effect
The brave soldier used it as a means of identification, irrespective of the conditions the platoon would be facing. In this picture here, soldiers are seen preparing to protect themselves from the rain, although funnily enough, they had tanks to face that day too.