Question

What proved to be the major stumbling block for Germany in Russia?

Answer 1

You're talking about World War II, right? Well, yeah, at one point Germany attempted to invade the Soviet Union (specifically during the Battle of Stalingrad.) But a major stumbling block was the weather in the Soviet Union; it was fiercely cold and German soldiers were starving and sick. Eventually, it became so cold that the German military retreated and Hitler's plans for "world domination" officially ended.