Mont Blanc (môN bläN) [key], Alpine massif, on the French-Italian border, SE of Geneva. One of its several peaks, also called Mont Blanc (15,771 ft/4,807 m), is the highest peak in France and the second highest in Europe. The southeastern (Italian) face is a massive wall; on the northwestern slopes are numerous glaciers, the largest of which (the Mer de Glace) flows into the valley of Chamonix, a famous French resort region and starting point for mountain climbers. There are many hotels and hostels along the base of Mont Blanc. The first successful ascent of Mont Blanc was made in 1786. In 1965 a highway tunnel (7.5 mi/12.1 km long) under Mont Blanc, linking Chamonix with Courmayeur, Italy, was opened to traffic. It provides a short, year-round route between Paris and Rome, as well as a link between the Geneva region and Italy. It was closed as a result of a fire from 1999 to 2002. The tunnel is one of the longest vehicular tunnels in the world.