The highest mountain in the Alps is Mont Blanc, at , on the Italian-French border. All the main peaks of the Alps can be found in the list of mountains of the Alps and list of Alpine peaks by prominence.
The Alps are generally divided into the Western Alps and the Eastern Alps. The division is along the line between Lake Constance and Lake Como, following the Rhine. The Western Alps are higher, but their central chain is shorter and curved; they are located in Italy, France and Switzerland. The Eastern Alps (main ridge system elongated and broad) belong to Austria, Germany, Italy, Liechtenstein, Slovenia and Switzerland. The highest peaks of the Western Alps are Mont Blanc, , Mont Blanc de Courmayeur , the Dufourspitze and the other summits of the Monte Rosa group, and the Dom, . The highest peak in the Eastern Alps is Piz Bernina, .
The Eastern Alps are commonly subdivided according to the different lithology (rock composition) of the more central parts of the Alps and the groups at its northern and southern fringes:
The Western Alps are commonly subdivided with respect to geography:
The geologic subdivision is different and makes no difference between the Western and Eastern Alps: Helveticum in the north, Penninicum and Austroalpine system in the centre and south of the Periadriatic seam the Southern Alpine system and parts of the Dinarides (see Alpine Geology). 'Geographically, the Jura mountains do not belong to the Alps; geologically'', however, they do.
The "main chain of the Alps" follows the watershed from the Mediterranean Sea to the Wienerwald, passing over many of the highest and most famous peaks in the Alps. From the Colle di Cadibona to Col de Tende it runs westwards, before turning to the north-west and then, near the Colle della Maddalena, to the north. Upon reaching the Swiss border, the line of the main chain heads approximately east-north-east, a heading it follows until its end near Vienna.
The Alps do not form an impassable barrier; they have been traversed for war and commerce, and later by pilgrims, students and tourists. Crossing places by road, train or foot are called passes. These are depressions in the mountains to which a valley leads from the plains and hilly pre-mountainous zones.
The Alps are a classic example of what happens when a temperate area at lower altitude gives way to higher elevation terrain. Elevations around the world which have cold climates similar to those found in polar areas have been called alpine. A rise from sea level into the upper regions of the atmosphere causes the temperature to decrease. The effect of mountain chains on prevailing winds is to carry warm air belonging to the lower region into an upper zone, where it expands in volume at the cost of a proportionate loss of heat, often accompanied by the precipitation of moisture in the form of snow or rain.
Little is known of the early dwellers in the Alps, save from the scanty accounts preserved by Roman and Greek historians and geographers. A few details have come down to us of the conquest of many of the Alpine tribes by Augustus. Also, recent research into Mitochondrial DNA indicates that MtDNA Haplogroup K very likely originated in or near the southeastern Alps approximately 12-15,000 years ago.
During the Second Punic War in 218 BC, The Carthaginian general Hannibal successfully crossed the alps along with an army numbering 38,000 infantry, 8,000 cavalry, and 37 war elephants. This was one of the most celebrated achievements of any military force in ancient warfare.
It is not until the final breakup of the Carolingian Empire in the 10th and 11th centuries that it becomes possible to trace out the local history of the Alps.
The higher regions of the Alps were long left to the exclusive attention of the people of the adjoining valleys, even when Alpine travellers (as distinguished from Alpine climbers) began to visit these valleys. The two men who first explored the regions of ice and snow were H.B. de Saussure (1740-1799) in the Pennine Alps, and the Benedictine monk of Disentis, Placidus a Spescha (1752-1833), most of whose ascents were made before 1806, in the valleys at the sources of the Rhine.
The Alps are popular both in summer and in winter as a destination for sightseeing and sports. Winter sports (alpine and Nordic skiing, tobogganing, snowshoeing, ski tours) can be practised in most regions from December to April, while in summer the Alps are popular with hikers, mountain bikers, paragliders, mountaineers, while many lakes attract swimmers, sailors and surfers. The lower regions and larger towns of the Alps are well accessed by motorways and main roads, but higher passes and by-roads can be treacherous even in summer. Many passes are closed in winter. A multitude of airports around the Alps (and some within), as well as long-distance rail links from all neighbouring countries, afford large numbers of travellers easy access from abroad.
This region is not always marked by the presence of the characteristic trees. Human interference has nearly exterminated them in many areas, and, except for the beech forests of the Austrian Alps, forests of deciduous trees are rarely found. In many districts where such woods once existed, they have been replaced by the Scots pine and Norway spruce, which are less sensitive to the ravages of goats who are the worst enemies of such trees.
Above the forestry, there is often a band of short pine trees (Pinus mugo), which is in turn superseded by dwarf shrubs, typically Rhododendron ferrugineum (on acid soils) or Rhododendron hirsutum (on basic soils). Above this is the alpine meadow, and even higher, the vegetation becomes more and more sparse. At these higher altitudes, the plants tend to form isolated cushions. In the Alps, several species of flowering plants have been recorded above , including Ranunculus glacialis, Androsace alpina and Saxifraga biflora.
Species common to the Alps. These are most numerous in the 15% of the Alps that are protected in parks and reserves.