The Biafo Glacier is a 67 km long glacier in the Karakoram Mountains of the Northern Areas, Pakistan which meets the 49 km long Hispar Glacier at an altitude of 5,128 m (16,824 feet) at Hispar La (Pass) to create the world's longest glacial system outside of the polar regions. This highway of ice connects two ancient mountain kingdoms, Nagar (immediately south of Hunza) in the west with Baltistan in the east. The traverse uses 51 of the Biafo Glacier's 63 km and all of the Hispar Glacier to form a 100 km glacial route. Scientists still are yet to find out how old this glacier actually is