I think Alt-Hist-Hub put it best,
People have nearly completely rebuilt Hiroshima and Nagasaki,
In ancient times it was so common to end a war by murdering everyone in the losing city and destroying all its infrastructure that we had come to believe real cities like Troy and even entire ancient empires like the Hittites were myths before we found their knocked over burned and flattened ruins.
There are several cities in central asia and the middle east that are either still or only now recovering from the amount of destruction unleashed on them during the mongol invasions. Had those events been set further back in history it is entirely possible we would never have known the names of cities like Samarkand or Baghdad.
Even with nuclear fire capable of glassing an entire planet we have managed to be far less war like than our ancestors.