The Loire (French pronunciation: ​[lwaʁ]; Occitan: Léger; Breton: Liger) is the longest river in France and the 171st longest in the world. With a length of 1,012 kilometres (629 mi), it drains an area of 117,054 km2 (45,195 sq mi), or more than a fifth of France's land area, while its average discharge is only half that of the Rhône. It rises in the highlands of the southeastern quarter of the Massif Central in the Cévennes range (in the department of Ardèche) at 1,350 m (4,430 ft) near Mont Gerbier de Jonc; it flows north through Nevers to Orléans, then west through Tours and Nantes until it reaches the Bay of Biscay (Atlantic Ocean) at Saint-Nazaire. Its main tributaries include the rivers Nièvre, Maine and the Erdre on its right bank, and the rivers Allier, Cher, Indre, Vienne, and the Sèvre Nantaise on the left bank. The Loire gives its name to six departments: Loire, Haute-Loire, Loire-Atlantique, Indre-et-Loire, Maine-et-Loire, and Saône-et-Loire. The central part of the Loire Valley, located in the Centre-Val de Loire region, was added to the World Heritage Sites list of UNESCO on December 2, 2000. Vineyards and châteaux are found along the banks of the river throughout this section. The human history of the Loire river valley begins with the Middle Palaeolithic period of 90–40 kya (thousand years ago), followed by modern humans (about 30 kya), succeeded by the Neolithic period (6,000 to 4,500 BC), all of the recent Stone Age in Europe. Then came the Gauls, the historical tribes in the Loire during the Iron Age period 1500 to 500 BC; they used the Loire as a major riverine trading route by 600 BC, establishing trade with the Greeks on the Mediterranean coast. Gallic rule ended in the valley in 56 BC when Julius Caesar conquered the adjacent provinces for Rome.