One where history has been altered in somd big massive way wherever that be
no moon landing
heroshima and nagasaki not being blown to pieces
one of the many coldwar close calls that has happened during history not being a cold War close call but instead a bbq so for an example Lt. Colonel Stanislav Petrov not going on his better judgement and reporting the false weather balloons to > higher soviet command or prehaps > B-59 Submarine if if wasn’t for one of those senior offices not putting in his key history as we know it would have been altered for the worse