I say Cannae and Hannibal's decision not to besiege Rome.
Had he been successful at taking Rome, there would be no Roman empire with all following consequences.
I read a book in which such a scenario was described, according to the author this would lead to dominance of the Celtic culture later on, as there would be no Romans to invade Gaul and Britain. The Celts would also possibly have resisted the barbarian invasions which resulted in most European countries that we know today.
Had he been successful at taking Rome, there would be no Roman empire with all following consequences.
I read a book in which such a scenario was described, according to the author this would lead to dominance of the Celtic culture later on, as there would be no Romans to invade Gaul and Britain. The Celts would also possibly have resisted the barbarian invasions which resulted in most European countries that we know today.