During the Second Punic War, Hannibal invaded Italy. He led the forces of Carthage against the Roman Republic, utilizing strategic tactics like crossing the Alps with war elephants. Hannibal's military genius surprised the Romans, achieving significant victories such as the Battle of Cannae. His invasion deeply threatened Rome, prompting the Republic to adapt its military strategies. The war ultimately led to a long struggle for supremacy in the Mediterranean, impacting Roman military and political development.