What was Hannibal's greatest military triumph over Rome?

The Battle of Cannae was a major battle of the Second Punic War that took place on 2 August 216 BC, in Apulia, in southeast Italy. The army of Carthage, under Hannibal, decisively defeated a larger army of the Roman Republic under the consuls Lucius Aemilius Paullus and Gaius Terentius Varro. It is regarded both as one of the greatest tactical feats in military history and as one of the worst defeats in Roman history.

During the battle the Roman's were lured into a box and when the Carthaginians closed in tight, the Roman's could no longer fight and were slaughtered. Rome lost, according to Polybius, 70,000 allied infantry were killed, 10,000 captured, and "perhaps" 3,000 survived. He also reports that of the 6,000 Roman and allied cavalry, only 370 survived.

This left Rome in disarray and demoralized to the point of resorting to human sacrifice. It also left Hannibal the run of the peninsula.