Mont Blanc lies between France and Italy, but the precise border line has been a subject of discussion since the 17th century. The two most famous cities near Mont Blanc are Chamonix, Haute-Savoie, (France) and Courmayeur, Valle d'Aosta, (Italy).
Begun in 1957 and completed in 1965, the 11.6 kilometer (7.25 mile) Mont Blanc Tunnel runs beneath the mountain between these two cities. It is one of the major trans-Alpine transport routes particularly for Italy, which relies on the tunnel for shipping as much as one-third of its freight to northern Europe.
The Mont Blanc massif is very popular for mountaineering, hiking, and skiing. The first time Mont Blanc was climbed was on August 8, 1786 by Jacques Balmat and Michel Paccard; the first woman to reach the summit, in 1808, was Marie Paradis.
The mountain has a number of glaciers streaming down its flanks; the Mer de Glace is the largest of these.