The Matterhorn is not the highest mountain in the Alps. It is not remotely close. Everybody recognises it anyway, and that comes down to a shape with a purely mechanical explanation.
The mountain is 4,478 metres high and stands right on the border between Switzerland and Italy, with Zermatt to the north and Breuil-Cervinia to the south. What makes it special is not the height but the fact that it stands alone, with four steep faces meeting at a point.
Four faces, four ridges
The faces point towards the four compass directions and are separated by four ridges. The north face is around 1,200 metres high and counts as one of the most serious walls in the Alps. The east face is roughly 1,000 metres, the south face 1,350 and the west face 1,400, making it the tallest of the four.
The ridges between them carry names that recur throughout climbing literature: the Hörnli ridge to the northeast, the normal route from Zermatt; the Zmutt ridge to the northwest; the Lion ridge to the southwest, the Italian normal route; and the Furggen ridge to the southeast. The last of these was not climbed until 1941.
How a horn forms
The shape is called a horn in geological terms, and it appears when several glaciers work on the same block of mountain at once.
A glacier hollows out a bowl-shaped niche in the mountainside, a cirque. Most of the work happens at the back wall of the niche: meltwater runs into cracks, freezes, expands and prises blocks loose. The wall therefore retreats into the mountain, year after year.
Put four such niches around the same block of mountain and let them work for roughly a million years. What remains between them is an ever narrower pyramid with sharp edges where the niches meet. The Matterhorn is not something that was built up; it is the remainder of something that was eaten away.
The same process happens on a smaller scale in Scandinavia. The difference is that our mountains were covered by a continuous ice sheet that ground the surrounding landscape down, while the alpine summits stood above the ice and kept their edges.
The summit comes from another continent
The strangest thing about the Matterhorn is not visible in the shape at all.
The mountain is built from stacked nappes, large sheets of rock thrust over one another when the Alps were folded. The rock at the very top is gneiss from the Dent Blanche nappe, which originated in the African plate. The base consists of rock with an entirely different origin.
In other words: the summit of the Matterhorn is a piece of Africa sitting on top of Europe. That is not a metaphor but a description of where the stone came from.
1865, and the price
The Matterhorn was one of the last great alpine summits to be climbed. Edward Whymper's party reached the top by the Hörnli ridge on 14 July 1865, after several failed attempts from both the Swiss and the Italian side.
On the descent one member of the party slipped and pulled three others with him. The rope between them broke, which saved the top three but meant four men fell. The accident made the Matterhorn world famous overnight, and it is still the reason this particular mountain carries such weight in the history of alpinism.
The mountain in a square
Capturing the Matterhorn in a square relief is unusually rewarding. The four faces mean the shape reads from any direction, and the dark areas where the walls drop away give depth even at a distance.
Our window covers about twelve kilometres, from Klein Matterhorn in the south up to Zermatt in the north, with the Theodul Pass and the Zmutt valley in the same frame. So it is not only the summit but the whole ski area around it, which means anyone who has skied there recognises their own terrain rather than just the postcard outline.
See the Matterhorn piece, or read on about why Mont Blanc's height changes every two years.