The Second Punic War was a conflict fought in 218 BC - 201 BC between Rome and Carthage. The majority of Carthaginian forces were led by Hannibal. Hannibal scared the Romans by invading them over the mountains from Hispania with war elephants. He won the Battle of the Trebia and kept winning battles by being a good general. In the Battle of Cannae he destroyed the biggest army the Romans had ever used. After that, the Romans avoided fighting Hannibal, and concentrated on defeating his allies. This became known as the Fabian strategy. Each side had many allies, but most of Rome's allies were loyal whilst Carthage's allies switched sides.
The Second Punic War ruined the power of Carthage. Rome became the dominant power in the Mediterranean Basin for the next 600 years.