On a hot summer day in 216 B.C., the Carthaginian general Hannibal Barca annihilated two armies of the Roman Republic in one of the most famous battles in ancient history; eight Roman legions were caught in Hannibal's vise where they suffered more than 50,000 deaths on the battlefield, a catastrophe which brought the Roman Republic to its knees. Hannibal's victory at Cannae has been discussed, dissected, and debated by soldiers, historians, and commentators ever since. Despite the defeat, Rome recovered remarkably quickly, demonstrating an unusual political, cultural, and military flexibility for the period. This presentation examines the Second Punic War, the Battle of Cannae, and how the Roman system not only absorbed these massive losses, but recovered and defeated Hannibal in the ensuing years, drastically impacting the history of the Western Mediterranean world. Additionally, Cannae's impact on tactical thought will briefly be surveyed to show how a battle fought more than two millennia ago still remains an important point of reference to modern generalship and warfare.