In relative terms 1945 was a high water mark.
None were stronger , none had come through the war with less ruined and lost.
Some good decisions were made in these days, integration and civil rights finally got on the right track and began to improve, if there was ever a period with more improvement in US civil rights than 1945-1965 I don't know what period this would be. The legacy of Eleanor Roosevelt, Harry Truman , and many others.
While in possession of all the worlds super weapons, the only fleet of long range bombers, the biggest navy afloat, the best equipped army the world had ever seen and the strongest production of materiel and food on the planet:- The US ramped down military spending and did not exploit this situation for anything worse than the establishment of the UN.
Since then Europe has healed from its wounds of WWII and is in some respects just as strong and productive. China has healed some from its losses in WWII and healed a bit from its losses in the era of "Great Leap Forward" is a superpower again after centuries of being a weak sister, attractive to empire builders.
To evaluate the question in the context of this planet, the end of WWII was a time of the USA being so strong relative to the rest of the world , that it was by the sufferance and assistance of the US that any other part of the world recovered.