Prussia was a major continental power, and then Hitler brought Germany back from the brink in the 3rd Reich, and now they are the bulwark of the EU. What has made this possible?
Well I can tell you about the third.
After WWII the allies and USSR poured a lot of resources into rebuilding Germany better than their cold war enemy. While the rest of the European countries had to rebuild with crippling loans and their own sweat, Germany was done quicker and much cheaper than the rest of Europe. It's funny, because the outcome of the war has been better for them in the long run.