2nd favorite commander of all time, behind Robert E. Lee.  Hannibal led his forces into a much larger empire and faced much larger forces than his.  Crossing the Alps is a huge accomplishment, but then to beat the Roman armies at Trebia, Lake Trasimene, and Cannae, he has earned his place as one of the finest generals the world has ever had.

Belongs on a Mount Rushmore for world military leaders. Leading an army comprised of many mercenaries in the first place, with Carthage being more of a mercantile empire to begin with? Losing thousands of men, war elephants etc to hostile tribes, steep passes, weather conditions, etc in an utterly ballsy but risky attempt to cross the Alps? Destroying the Roman forces several times on their own turf and staying in Italy for 15 years with a vastly outnumbered army? To be fair, Scipio Africanus was a great general, he doesn't always get enough credit, and had to be great to beat this guy, but although he eventually lost the war, was betrayed by the merchants and leaders of his own people, got chased around the ancient world, and finally wound up commiting suicide before they captured him, the achievements of Hannibal are nothing short of breathtaking.