The Alps are a crescent shaped geographic feature of central Europe that ranges in a 800 km (500 mi) arc from east to west and is 200 km (120 mi) in width. The mean height of the mountain peaks is 2.5 km (1.6 mi).[10] The range stretches from the Mediterranean Sea north above the Po basin, extending through France from Grenoble, and stretching eastward through mid and southern Switzerland. The range continues onward toward Vienna, Austria, and east to the Adriatic Sea and Slovenia.[11][12][13] To the south it dips into northern Italy and to the north extends to the southern border of Bavaria in Germany.[13] In areas like Chiasso, Switzerland, and Allgäu, Bavaria, the demarcation between the mountain range and the flatlands are clear; in other places such as Geneva, the demarcation is less clear. The countries with the greatest alpine territory are Switzerland, France, Austria and Italy.
The highest portion of the range is divided by the glacial trough of the Rhone valley, with the Pennine Alps from Mont Blanc to the Matterhorn and Monte Rosa on the southern side, and the Bernese Alps on the northern. The peaks in the easterly portion of the range, in Austria and Slovenia, are smaller than those in the central and western portions.[13]
The variances in nomenclature in the region spanned by the Alps makes classification of the mountains and subregions difficult, but a general classification is that of the Eastern Alps and Western Alps with the divide between the two occurring in eastern Switzerland according to geologist Stefan Schmid,[6] near the Splügen Pass.
The highest peaks of the Western Alps and Eastern Alps, respectively, are Mont Blanc, at 4,810 m (15,780 ft)[14] and Piz Bernina at 4,049 metres (13,284 ft). The second-highest major peaks are Monte Rosa at 4,634 m (15,200 ft) and Ortler[15] at 3,905 m (12,810 ft), respectively
Series of lower mountain ranges run parallel to the main chain of the Alps, including the French Prealps in France and the Jura Mountains in Switzerland and France. The secondary chain of the Alps follows the watershed from the Mediterranean Sea to the Wienerwald, passing over many of the highest and most well-known peaks in the Alps. From the Colle di Cadibona to Col de Tende it runs westwards, before turning to the northwest and then, near the Colle della Maddalena, to the north. Upon reaching the Swiss border, the line of the main chain heads approximately east-northeast, a heading it follows until its end near Vienna.
