Task: Question Generation
Input (English): The Romans held off Hannibal in three battles, but then Hannibal smashed a succession of Roman consular armies. By this time Hannibal's brother Hasdrubal Barca sought to cross the Alps into Italy and join his brother with a second army. Hasdrubal managed to break through into Italy only to be defeated decisively on the Metaurus River. Unable to defeat Hannibal on Italian soil, the Romans boldly sent an army to Africa under Scipio Africanus to threaten the Carthaginian capital. Hannibal was recalled to Africa, and defeated at the Battle of Zama.
Output (English): At what river was Hasdrubal Barca defeated at?