The Alps (/ælps/)[a] are one of the highest and most extensive mountain ranges in Europe,[b][2] stretching approximately 1,200 km (750 mi) across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia.

Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn.

[11] An alp refers to a high mountain pasture, typically near or above the tree line, where cows and other livestock are taken to be grazed during the summer months and where huts and hay barns can be found, sometimes constituting tiny hamlets.

[39] The Tethys was later squeezed between colliding plates causing the formation of mountain ranges called the Alpide belt, from Gibraltar through the Himalayas to Indonesia—a process that began at the end of the Mesozoic and continues into the present.

[45] Similarly the peaks in eastern Switzerland extending to western Austria (Helvetic nappes) consist of thin-skinned sedimentary folding that detached from former basement rock.

[40] The core regions of the Alpine orogenic belt have been folded and fractured in such a manner that erosion produced the characteristic steep vertical peaks of the Swiss Alps that rise seemingly straight out of the foreland areas.

[54] The underlying mechanisms that jointly drive the present-day uplift pattern are the isostatic rebound due to the melting of the last glacial maximum ice-cap or long-term erosion, detachment of the Western Alpine subducting slab, mantle convection as well as ongoing horizontal convergence between Africa and Europe, but their relative contributions to the uplift of the Alps are difficult to quantify and likely to vary significantly in space and time.

In the 20th century Robert Parker wrote a well-known work about the rock crystals of the Swiss Alps; at the same period a commission was established to control and standardize the naming of Alpine minerals.

[56] In the Miocene Epoch the mountains underwent severe erosion because of glaciation,[43] which was noted in the mid-19th century by naturalist Louis Agassiz who presented a paper proclaiming the Alps were covered in ice at various intervals—a theory he formed when studying rocks near his Neuchâtel home which he believed originated to the west in the Bernese Oberland.

[16] The Rhône is second to the Nile as a freshwater source to the Mediterranean Sea; the river begins as glacial meltwater, flows into Lake Geneva, and from there to France where one of its uses is to cool nuclear power plants.

Furthermore, the decrease of glaciated areas combined with a succession of winters with lower-than-expected precipitation may have a future impact on the rivers in the Alps as well as an effect on the water availability to the lowlands.

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 temperature, often accompanied by precipitation in the form of snow or rain.

[75] The height of the Alps is sufficient to divide the weather patterns in Europe into a wet north and dry south because moisture is sucked from the air as it flows over the high peaks.

[78] Various models of climate change have been projected into the 22nd century for the Alps, with an expectation that a trend toward increased temperatures will have an effect on snowfall, snowpack, glaciation, and river runoff.

[94] The vegetation has changed since the second half of the 20th century, as the high alpine meadows cease to be harvested for hay or used for grazing which eventually might result in a regrowth of the forest.

[126] Radiocarbon-dated charcoal placed around 50,000 years ago was found in the Drachloch (Dragon's Hole) cave above the village of Vattis in the canton of St. Gallen, proving that the high peaks were visited by prehistoric people.

Later the first wave of Romanticism such as Johann Wolfgang von Goethe, and J. M. W. Turner came to admire the Alpine scenery;[140] Wordsworth visited the area in 1790, writing of his experiences in The Prelude (1799).

At the end of the Napoleonic Wars, the Alpine countries began to see an influx of poets, artists, and musicians,[141] as visitors came to experience the sublime effects of monumental nature.

When Coleridge travelled to Chamonix, he declaimed, in defiance of Shelley, who had signed himself "Atheos" in the guestbook of the Hotel de Londres near Montenvers,[143] "Who would be, who could be an atheist in this valley of wonders".

In the early years of the "golden age of alpinism" initially scientific activities were mixed with sport, for example by the physicist John Tyndall, with the first ascent of the Matterhorn by Edward Whymper being the highlight.

The first president of the Alpine Club, John Ball, is considered the discoverer of the Dolomites, which for decades were the focus of climbers like Paul Grohmann, Michael Innerkofler and Angelo Dibona.

[152] Smugglers of humans claim that crossing the Alps is less dangerous, or deadly, than traveling 355 km on water between Tripoli and Lampedusa with a tramp ship (carretta del mare) or a dinghy.

Larger cities outside the Alps are Milan, Verona, Turin (Italy), Munich (Germany), Graz, Vienna, Salzburg (Austria), Ljubljana, Maribor, Kranj (Slovenia), Zurich, Geneva (Switzerland), Nice and Lyon (France).

[156] Much of the Alpine culture is unchanged since the medieval period when skills that guaranteed survival in the mountain valleys and the highest villages became mainstays, leading to strong traditions of carpentry, woodcarving, baking, pastry-making, and cheesemaking.

In mid-June, cows are moved to the highest pastures close to the snowline, where they are watched by herdsmen who stay in the high altitudes often living in stone huts or wooden barns during the summers.

The Almabtrieb, Alpabzug, Alpabfahrt, Désalpes ("coming down from the alps") is celebrated by decorating the cows with garlands and enormous cowbells while the farmers dress in traditional costumes.

Frequently they include music (e.g. the playing of Alpenhorns), dance (e.g. Schuhplattler), sports (e.g. wrestling marches and archery), as well as traditions with pagan roots such as the lighting of fires on Walpurgis Night and Saint John's Eve.

[161][162] The Alps are one of the more popular tourist destinations in the world with many resorts such as Oberstdorf, in Bavaria, Saalbach in Austria, Davos in Switzerland, Chamonix in France, and Cortina d'Ampezzo in Italy recording more than a million annual visitors.

[168] During the post-World War I period, ski lifts were built in Swiss and Austrian towns to accommodate winter visitors, and summer tourism continued to be important.

[174] The lower regions and larger towns of the Alps are well-served by motorways and main roads, but higher mountain passes and byroads, which are amongst the highest in Europe, can be treacherous even in summer due to steep slopes.