The Cannae Battlefield (216 BC), a pivotal engagement during the Second Punic War, led to the destruction of one of the largest consular armies ever raised by the Republic. Historians have for centuries paid the utmost attention to unitby- unit dispositions and tactical maneuvers without studying the local geology and particularly the geomorphology of the battle site. A brief traverse over the battle site, adjacent to the museum in 2004, led to a hidden defile, heretofore not mentioned in the literature, one which may have helped turn the tide for the Carthaginians, and offering prospect of further geoarchaeological investigation.