Even today it is considered one of the greatest military feats ever. In 218 BC, a Carthaginian army of ninety thousand men and three dozen elephants set out to cross the Alps to challenge the might of Rome. The exact route chosen by Hannibal, its charismatic commander, has been a matter of dispute ever since. Now, researchers believe they might be able to track his route. It is one of the mysteries of history, which way the Carthaginian commander Hannibal took in 218 BC to cross the Alps.