Mont Blanc

• 1. Introduction

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  Mont Blanc has a summit that nobody can measure once and for all. Its crown is a thick dome of ice and snow, and the thickness of that dome shifts over time. Surveyors can state the height on a given day, but never for good.

  The mountain stands in the French Alps, right on the border with Italy, at roughly 4,800 metres. It is the highest peak in Europe outside the Caucasus Mountains. Around its base sit Chamonix and Saint-Gervais-les-Bains in France and Courmayeur in Italy. Chamonix was the site of the first Winter Olympics.

  Several questions run through this story. Who first stood on the top, and what did that climb start? Which country can rightfully claim the summit? What did engineers try to build on the ice, and what did they bore beneath it? And why do so many people still walk up toward a place that has killed so many?

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• 2. First Ascent

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  The name Mont Blanc first appears in print on a 1744 map and sketch of the Chamonix valley drawn by Pierre Martel. By then the peak already had a long record of rank. It had been the highest mountain of Charlemagne's Frankish Empire, and it stayed the highest of the Holy Roman Empire until 1792.

  In 1760, the Swiss naturalist Horace-Bénédict de Saussure began traveling to Chamonix to study the mountain. He tried to reach the top with Jean-Laurent Jordaney, a mountain guide from Courmayeur who was born in Pré-Saint-Didier. Jordaney had been at Saussure's side since 1774, on the Miage Glacier and on Mont Crammont.

  The first recorded ascent came on the 8th of August 1786. The climbers were Jacques Balmat and a doctor named Michel Paccard. Saussure had set the climb in motion and rewarded the men for succeeding. At that moment the summit belonged to neither France nor Italy, because neither country existed in its later form. Tradition marks this climb as the start of modern mountaineering.

  It took more than two decades for a woman to follow. In 1808, Marie Paradis became the first woman to reach the summit.

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• 3. A Moving Summit

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  In 2002, the French mapping agency IGN and a group of expert surveyors used GPS to fix the summit at 4807.40 metres. For a long time before that, the official figure had simply been 4807 metres. Then came the European heatwave of 2003.

  On the 6th and the 7th of September that year, a new team went up to measure again. It included the glaciologist Luc Moreau, two surveyors from the GPS Company, three people from the IGN and seven expert surveyors. Four mountain guides from Chamonix and Saint-Gervais joined them, along with four students from various French institutes.

  They recorded 4808.45 metres. The highest point had also moved, sitting 75 centimetres from where it lay in 2002. Afterward, more than 500 points were measured to study how climate change and height fluctuations behave at different spots. Since then, the mountain has been measured every two years.

  The results of the 2005 survey were published on the 16th of December 2005. They gave 4808.75 metres, which is 30 centimetres above the previous figure. That survey also placed the bare rock summit at 4792 metres, about 40 metres west of the ice-covered top.

  The numbers kept wandering. The summit measured 4807.9 metres in 2007 and 4807.45 metres in 2009. In 2013 it read 4810.02 metres, and in 2015 it read 4808.73 metres. The figure for 2021 was 4,807.81 metres. In 2023 it fell to 4,805.59 metres, the lowest of these readings, after 18 months of drought in the Western Alps. In 2025 it rose again to 4807.3 metres.

  On a clear day from the top, the eye can reach the Jura, the Vosges, the Black Forest and the Massif Central, along with the main summits of the Alps.

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• 4. Granite and Weather

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  A huge body of granite, called a batholith, makes up most of Mont Blanc and its neighbors. It was forced upward through older layers of gneiss and mica schist during the Variscan mountain-building event of the late Palaeozoic period. The summit sits exactly where these two kinds of rock meet.

  The contact is not the same everywhere. To the southwest the granite pushes into its surroundings, while to the northeast the boundary turns tectonic. The granites are mostly very coarse-grained and range from microgranites to porphyroid granites. The whole massif tilts toward the north-west. Near-vertical faults running north to south cut it during the Variscan event, and later shear zones formed in the Alpine event. Repeated phases of movement broke the rock along many overlapping planes, and glaciers, past and present, carved it into its current shape.

  In 1873, Venance Payot published the first systematic account of the minerals around Mont Blanc. His list, titled "Statistique minéralogique des environs du Mt-Blanc", catalogued 90 mineral types, counting some that occur only in tiny amounts in rocks. Leave those out, and at least 68 separate mineral species are known across the wider massif today.

  The massif lies on the watershed between the Rhône and the Po. It also sits between the climate of the northern and western Alps and that of the southern Alps. Conditions on the Mer de Glace resemble those on the northern side of the Swiss Alps. The climate is cold and temperate, and altitude shapes it strongly.

  Rainfall and snowfall change in a surprising way with height. Chamonix, at about 1030 metres, gets around 1020 millimetres of precipitation a year. The Col du Midi, at 3500 metres, receives 3100 millimetres. Near the summit, at 4300 metres, the total drops back to only about 1100 millimetres.

  The highest ground produces its own weather. The summit is a permanent ice cap with temperatures around -20 C, and it is prone to strong winds and sudden changes.

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• 5. A Disputed Border

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  About 65 hectares of Mont Blanc and 10 hectares of the Dôme du Goûter are claimed by two countries at once. Along most of the massif, the border between Italy and France follows the main Alpine watershed, from the Aiguille des Glaciers to Mont Dolent, where Switzerland begins. Near these two summits, however, the line is contested.

  Italian officials say the border keeps to the watershed, which would split both summits between Italy and France. French officials say the border avoids both summits and leaves them entirely in France.

  The roots of the argument reach back to 1723, when Victor Amadeus II, the Duke of Savoy, acquired the Kingdom of Sardinia. The state of Sardinia later became the leading force in Italian unification. France points to the Treaty of Paris of 1796. In France's reading, the old border between Savoy and Piedmont departed from the watershed and placed the whole summit inside Savoy, and so inside France.

  After the Napoleonic Wars, the Congress of Vienna restored the King of Sardinia to Savoy, Nice and Piedmont, overruling the 1796 treaty. Forty-five years later, after the Second Italian War of Independence, a new act replaced it. Napoleon III and Victor Emmanuel II of Savoy signed it in Turin on the 24th of March 1860. It covered the annexation of Savoy and followed French neutrality during plebiscites in Tuscany, Modena, Parma and Romagna. A demarcation agreement of the 7th of March 1861 then drew the new border. With Italy now formed, Mont Blanc stood for the first time on the French-Italian frontier.

  Both governments still treat the 1860 act as valid. Italy argues that France moved the border in 1865, when a survey by the French army cartographer Captain JJ Mieulet put the summit inside French territory. The result, Italy says, was a line that left the watershed and a set of maps that no longer matched those published in Italy.

  Swiss mapping from the Federal Office of Topography marks a zone labeled statut de territoire contesté around both summits. It offers two readings. In one, the summits straddle the ridgeline and are shared equally. In the other, both summits, and less clearly that of Mont Blanc de Courmayeur, lie wholly in France.

  NATO maps follow the Italian mapping agency, the Istituto Geografico Militare, which rests on treaties it considers in force.

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• 6. Building Into Mont Blanc

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  In 1890, the astronomer Pierre Janssen, director of the Meudon astrophysical observatory, began to consider an observatory on the very top of Mont Blanc. Gustave Eiffel agreed to take the project on, but only if solid rock could be found within 12 metres below the ice. In 1891, the Swiss surveyor Imfeld dug two horizontal tunnels, each 23 metres long, at a depth of 12 metres under the ice summit. He found nothing solid, and the Eiffel project was dropped.

  The observatory went up anyway, in 1893. That January, a cold wave pushed the temperature on Mont Blanc to -43 C, the lowest ever recorded there. Levers fixed to the ice held the building up, and for some time this worked. By 1906 the structure was leaning heavily. Moving the levers eased the tilt a little. Three years later, two years after Janssen died, a crevasse began to open beneath it. The observatory was abandoned, the building eventually collapsed, and only the tower was rescued at the last moment.

  The mountain has been crossed from the inside as well. A cable car rises from Courmayeur and crosses the range through the Col du Géant to Chamonix. Lower down, a drilling project began in 1946 to carve a road tunnel beneath the massif. Construction ran from 1957 to 1965, and the Mont Blanc Tunnel opened to vehicles in 1965 at 11,611 metres long. It became a major transport route across the Alps, linking Chamonix in France with Courmayeur in Italy.

  In 1999, a transport truck caught fire inside the tunnel, and the blaze raged out of control. Thirty-nine people died. The tunnel was rebuilt with computerised detection equipment, extra security bays, a parallel escape shaft and a fire station in the middle of the tunnel. Vents push clean air through the escape shafts, and anyone in a security bay now has live video contact with the control centre.

  Trucks are also checked before they enter. Inspection sites at Aosta in Italy and Passy-Le Fayet in France examine cargo and double as staging areas that control commercial traffic at peak hours. The tunnel reopened three years after the disaster.

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• 7. Routes and Risks

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  An average of 20,000 mountaineer tourists reach the summit of Mont Blanc each year. The most popular path is the Goûter Route, which is also called the Voie des Cristalliers or the Voie Royale. Climbers start at Saint-Gervais-les-Bains and take the Tramway du Mont-Blanc to the Gare du Nid d'Aigle. They walk toward the Tête Rousse refuge and cross the Grand Couloir, also known as the Goûter Corridor, where rockfalls are frequent. They sleep at the Goûter Hut. On the second day they pass the Dôme du Goûter, the emergency Vallot cabin and the Arête des Bosses.

  The Voie des 3 Monts, also called La Traversée, begins in Chamonix with the cable car to the Aiguille du Midi. Climbers sleep at the Cosmiques Hut and then climb over Mont Blanc du Tacul and Mont Maudit. From the cable car stop, the summit looks close, 1000 metres higher. Yet this route is more technical than the common ones and crosses two other 4,000-metre peaks before the final 1,000-metre push.

  The usual Italian route, La route des Aiguilles Grises, crosses the Miage Glacier and spends the night at the Gonella refuge. A longer crossing links Miage, Bionnassay and Mont Blanc over three days. It starts at Contamines-Montjoie and uses the Conscrits Hut and the Durier cabin.

  A 1994 estimate put alpinist deaths on Mont Blanc at 6,000 to 8,000 in total, more than on any other mountain. That figure leaves out two planes that struck the peak. Air India Flight 245 crashed in 1950 and Air India Flight 101 in 1966. Both were approaching Geneva Airport, and both pilots misjudged their descent. In all, 48 and 117 people died. Among the dead on Flight 101 was the nuclear scientist Homi J. Bhabha, known as the father of India's nuclear programme.

  Media reports sometimes claim that 100 hikers die each year, but no evidence backs that. Reported yearly deaths since the 1990s run from 10 to 20. In 2017, fourteen people died among 20,000 summit attempts, and two more stayed missing. By August 2018 the count was 15.

  The Goûter couloir is the worst stretch. A French study found 74 deaths between the Tête Rousse refuge, at 3,187 metres, and the Goûter refuge, at 3,830 metres, from 1990 to 2011. Another 17 followed in 2012-15. There were none in 2016, and 11 in 2017. On the busiest weekends, usually around August, the local rescue service averages 12 missions.

  Climate change is rewriting the routes. In 2015, crevasse fields made the old Grand Mulets route virtually impassable. The Goûter Hut was closed for some days by municipal decree because of very high rockfall danger, and helicopters evacuated stranded climbers. In 2016, a crevasse opened at high altitude near the end of the climb shared by the Goûter and Grand Mulets routes. It was a sign of glacial movement not seen before.

  Speed has become its own contest on the mountain. On the 11th of July 2013, Kilian Jornet set the fastest overall ascent and descent time at 4 hours, 57 minutes and 40 seconds. On the 21st of June 2018, Emelie Forsberg set a women's fastest known time from Chamonix of 7 hours, 53 minutes and 12 seconds. She had earlier run 8 hours, 10 minutes in 2013. On the 17th of June 2023, Hillary Gerardi lowered the women's mark to 7 hours, 27 minutes and 39 seconds. She chose the longer but safer Arête Nord because of serac fall.

  Children have also ended up in trouble. In July 2014, the American entrepreneur Patrick Sweeney tried for a record with his nine-year-old son and 11-year-old daughter. An avalanche caught them, they survived, and they gave up. In August 2014, mountain gendarmes stopped an Austrian climber and his five-year-old son at 3,200 metres. On the 5th of August 2017, a helicopter rescued nine-year-old Hungarian twins and their mother from 3,800 metres while their father and a family friend carried on.

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• 8. Poets and Protection

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  The poet Samuel Taylor Coleridge wrote Hymn Before Sunrise, in the Vale of Chamouni. Percy Shelley wrote a poem called Mont Blanc. Lord Byron's Manfred and Mary Shelley's Frankenstein; or, The Modern Prometheus also draw on the mountain. William Wordsworth gave it a place in Book VI of The Prelude. Letitia Elizabeth Landon wrote a poem to accompany an engraving of a painting by J. M. W. Turner. Jon Krakauer's Eiger Dreams and Roger Frison-Roche's Premier de cordée belong to the mountaineering shelf, and Premier de cordée was also made into a television film.

  The screen has returned to Mont Blanc many times. Abel Gance's La Roue, from 1923, runs 273 minutes and shows railway workers and families in south-eastern France, including the Mont Blanc area. In 1930, Arnold Fanck directed Storm over Mont Blanc, with Leni Riefenstahl. Jean-Luc Prévost made a 1984 documentary, La Terre, son visage, in which Haroun Tazieff describes crossing the mountain from west to east. The BBC adaptation of John Christopher's Tripods trilogy ran for 25 episodes over two seasons in 1985-86. Its heroes travel to Mont Blanc, where a group of humans live free of the Tripods' rule.

  The massif is now proposed as a World Heritage Site because of its standing as the birthplace and symbol of modern mountaineering. Listing would need Italy, France and Switzerland to make the request to UNESCO together.

  As one of the most visited destinations in the world, the mountain is seen by some as under threat. In 2002, Pro-Mont Blanc, an international collective of associations working to protect it, published Le versant noir du mont Blanc, or The black hillside of Mont Blanc, which sets out present and future problems of conservation.

  One of the more unusual measures came in 2007. Helicopters carried Europe's two highest toilets, at 4,260 metres, to the upper mountain, and helicopters service them too. They are meant to serve 30,000 skiers and hikers a year and to reduce the waste that washes down the slopes in the spring thaw.

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