Scientists may have finally solved the 2,200-year-old mystery of Hannibal's legendary Alpine crossing.In 218 BC, the young Carthaginian general marched 40,000 men, 7,000 horses, and 37 war elephants across the Alps into Italy to wage war against Rome.For hundreds of years, historians have struggled to pin down the exact route of military history's greatest journey.But now scientists have used the science of elephant athletics to trace Hannibal's steps through the mountains.With historical evidence so sparse, researchers used modelling based on modern African elephants to estimate how much energy each possible route would require.This revealed that the most popular theory, the Col du Clapier route, would have been one of the most arduous options available.Instead, the researchers found that the most efficient route would have been to take the Col de la Traversette, a mountain pass connecting France and Italy at 9,669 feet (2,947 m).This would have used between 11 and 19 per cent less energy than the alternative options - making it the most likely path for a pack of exhausted soldiers. Scientists have revealed the route that Hannibal might have used to cross the Alps in 218 BC, showing that the Col de la Traversette would have been the most efficient route