I.

Introduction

Alps, great mountain system of south central Europe, forming an arc some 1,200 km (750 mi) long from the Gulf of Genoa (see Ligurian Sea) to the River Danube at Vienna. The Alps are the highest and most densely settled mountain belt of Europe, occupying an area of about 240,000 sq km (92,700 sq mi) and inhabited by some 20 million people. The valleys of the Alps are areas of year-round settlement; the flatter upland tracts comprise pastures and seasonally inhabited settlements, and the zone above the tree line serves as pasture and for recreation. Important economic activities include tourism, dairy farming, forestry, the production of hydroelectric power, and the extraction of salt and iron ore. With its important pass routes between central and southern Europe, the Alps have been an area of transit trade since ancient times.