One of the most accurate ancient battle depictions in modern media.
Swearing vengeance against Rome for the humiliation they inflicted on Carthage, Hannibal Barca in his Iberian kingdom set out on an audacious plan to strike at Rome's heart in Italy, by marching an army of between 60,000 and 80,000 men overland through southern Gaul and over the Alps.
Somewhere over 40,000 arrived in Italy with Hannibal some months later.
With inferior numbers, Hannibal wielded a tactical and strategic genius which allowed him to twice outsmart and defeat the Roman armies at Lake Trasimene and the River Trebia.
Appointed Dictator by the Senate of Rome, Quintus Fabius Maximus was not about to let Hannibal demolish and humiliate the Romans again. He began a policy of "delaying", a war of attrition which would starve Hannibal's army out of Italy.
This policy lasted as long as Fabius Maximus's Dictatorship. After it expired, the new Consuls for the year, Gaius Terentius Varro and Lucius Aemilius Paullus, raised an army of some 16 legions numbering between 80,000 and 90,000 men, Roman and Italian, to meet Hannibal Barca and defeat him once and for all.
The ensuing day's battle would be the turning point for the Second Punic War, and the course of Roman and Carthaginian history. Hannibal's tactics would be studied and admired by Rome for hundreds of years to come.
The strategy, as it unfolded, began by presenting Rome with an unavoidably appealing target---the Carthaginian infantry line, slightly ragged, shaped like a crescent. The cavalry met first, with Hannibal's Iberian, Gallic, and Carthaginian cavalry quickly defeating the Romans, and chasing them off the field completely. The Roman army pressed into the infantry, which gave ground steadily, flexing the crescent shape around and creating a sort of crater for the front lines of the Romans to crash into. Much of the center would be stuck in place by the sheer mass of the army moving forward.
On cue, the elite African and Libyan troops of Hannibal's army extended the lines and attacked the Roman flanks, leaving one line of escape. This was sealed shut by the returning heavy cavalry. While virtually every Carthaginian line could fight the Romans, only the Roman lines on the extreme flanks, rear, and front could fight while the rest were crushed in the center, left to panic that they were surrounded, and undoubtedly losing the battle.
Estimates put the Roman casualties at 50,000, with Consul Paullus dead, and over eighty Roman Senators killed. Carthage lost 6,000 dead and 10,000 wounded.
Despite the stunning victory, Hannibal Barca did not press on Rome itself. Theories range, claiming Hannibal could have taken Rome by force, while others put forth that because Barca had no siege equipment, he would have bled his army out on the walls, as the Romans had left a garrison in the city, and would scrape together all the troops they could to defend the city to the death.
Hannibal was ultimately defeated by Publius Cornelius Scipio at the Battle of Zama, after spending over a decade in Italy, victim of returning Dictator Quintus Fabius Maximus's "delaying" tactics, an entire Roman army keeping Hannibal pinned in Italy while Scipio led another army to ultimately destroy Hannibal's "kingdom" in Iberia. Hannibal risked the journey to Carthage with his ragged army when Carthage itself was threatened by Rome.