To avoid indulging in ASB, I assume the idea is that Europe has evolved to modern days with modern weapons yet retained the same Great, Major and Minor powers of circa 1914. If they accomplish this without any wars such as WW1 or 2, then they had a fair share of proxy wars or a war in Asia not threating enough to spark a fight back home or something uniting Europe to assert renewed domination, such a war(s) to spur weapon development along with doctrine yet without the other costs. If they learned how to do this then they are just sitting in one long standing Cold War, the nuclear arsenals negate adventurism in Europe. Or they got past the July Crisis and the reality of trade linkages increasingly made war too costly to indulge in, the Europeans stood down to rather anemic defense forces aside from what may be needed to police shipping lanes and quell colonial issues, and it is all Waltzes, rainbows and happiness. Unfortunately too many jumping off points for a big war before the nuclear option quells things.