Mont Blanc massif

The Mont Blanc massif is a mountain range in the Alps, located mostly in France and Italy, but also straddling Switzerland at its northeastern end. It contains eleven major independent summits, each over 4,000 metres (13,123 ft) in height. It is named after Mont Blanc (4,808 metres (15,774 ft)), the highest point in western Europe and the European Union. Because of its considerable overall altitude, a large proportion of the massif is covered by glaciers, which include the Mer de Glace and the Miage Glacier – the longest glaciers in France and Italy, respectively. The massif forms a watershed between the vast catchments of the rivers Rhône and Po, and a tripoint between France, Italy and Switzerland; it also marks the border between two climate regions by separating the northern and western Alps from the southern Alps. The mountains of the massif consist mostly of granite and gneiss rocks and at high altitudes the vegetation is an arctic-alpine flora. The valleys that delimit the massif were used as communication routes by the Romans until they left around the 5th century AD. The region remained of some military importance through to the mid-20th century.