Cav is right in 1939-40 Germany defeated the armies of Poland, France, Britain, Belgium, the Netherlands, Denmark, Norway, Latvia, Estonia, and Lithuania. Only
the first two were major military powers, the Poles had modern French aircraft but most of them were destroyed on the ground. Polish pilots were very well trained, and lacked for nothing in motivation in combat during the Battle of Britain. Poland was also fighting on two fronts.
Personally I reserve my admiration mostly for the Poles, Czechs, French etc that came to England in 1940 when all must have seemed lost, and defeat barbarism and slavery or death the likely prospect. They and the men and women of Britain, stood alone against an unbeaten war machine from 1940 until 1942.
I remember my mother telling me that it wasn't until the defeat of the Germans at Stalingrad in 1943, that people began to feel confident that the allies would win. They endured the bombing raids, the rationing, the defeats. What little material assistance provided by the USA had to paid for in full, upfront. They still had food rationing in the UK up until 1947.