Mont Blanc Tunnel Between France and Italy Opens Summary

  • Last updated on November 10, 2022

The Mont Blanc tunnel was one of the greatest engineering feats in Europe in the post-World War II period. The project, a cooperative effort between Italy, France, and Switzerland, produced a 7.25-mile tunnel and greatly facilitated European economic unity.

Summary of Event

The Mont Blanc tunnel was a political challenge for its visionaries and also an engineering feat of an unprecedented nature. The tunnel, cut through the 15,781-foot Mont Blanc at an altitude of 4,000 feet, also connected two famed ski resorts, Chamonix in France and Courmayeur in Italy. In an area where roads were often blocked five to six months of the year, the tunnel became an all-weather route that shortened the distance between Paris and Rome by 195 miles. Tunnels Mont Blanc Tunnel [kw]Mont Blanc Tunnel Between France and Italy Opens (July 16, 1965) [kw]Tunnel Between France and Italy Opens, Mont Blanc (July 16, 1965) [kw]France and Italy Opens, Mont Blanc Tunnel Between (July 16, 1965) [kw]Italy Opens, Mont Blanc Tunnel Between France and (July 16, 1965) Tunnels Mont Blanc Tunnel [g]Europe;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [g]France;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [g]Italy;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [g]Switzerland;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [c]Engineering;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [c]Architecture;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [c]Transportation;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [c]Science and technology;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] [c]Diplomacy and international relations;July 16, 1965: Mont Blanc Tunnel Between France and Italy Opens[08440] Saussure, Horace Bénédict de Totino, Dino Lora Giscard d’Estaing, Edmond

Soon after explorer Horace Bénédict de Saussure’s first ascent of the mountain in 1787, there had been calls to tunnel through it. During the decade before World War I, Frenchman Arnold Monod Monod, Arnold drafted a plan for a railroad tunnel through the mountain, but in 1928, he organized a Franco-Italian study group to plan a motorway instead of a railroad tunnel. The rise of Italian dictator Benito Mussolini and tensions over Ethiopia deferred these efforts until after 1945.

One important figure in the tunnel story was Dino Lora Totino, an Italian entrepreneur. Totino had constructed rail routes on the Matterhorn and a cable-car lift over Mont Blanc. In 1946 he started tunnel excavations on his own, hoping that his actions would be backed by the Italian government. In 1947 the Italians did extend support. Totino’s energies then focused on persuading the French to join in. The French were resistant to the venture, in part because of the perception that the mountain served as a defensive barrier.

Totino’s efforts were rewarded on March 14, 1953, when a preliminary agreement was reached between France and Italy on the construction and operation of the proposed tunnel through Mont Blanc. According to the terms of the agreement, the construction of the tunnel was to be put in the hands of two companies, one French and the other Italian, each responsible for one-half of the work. A commission of surveillance, composed of six members—three Italian and three French—had responsibility for overall coordination of the project. After the tunnel was completed and opened, the construction companies would form a multinational firm that collected tolls and provided necessary maintenance.

It took another six years, however, before the digging began. French and Swiss national railway interests were against any roadway development. Certain French interests wanted tunnels on the non-Italian side of the Alps, and there were Swiss constituencies that wanted to tunnel the Grand-Saint-Bernard, an alpine pass between Switzerland and Italy, hoping to attract both tourists and coal and steel traffic. Furthermore, there were regional issues in France, as powerful Rhône Valley businesses in Marseille and Lyon, along with those from Côte d’Azur and Savoy, campaigned for either a new road in their own vicinity or the existing road that they claimed could be improved so that it would be usable year round. Their main fear, however, was that the new Mont Blanc tunnel would divert trade from Marseille to Genoa, since the latter port had lower fees.

Resistance from these interest groups was eventually overcome, however, and on January 24, 1957, the French assembly, by a vote of 544 to 32, ratified a bill authorizing French participation in the project. With the organization of the respective construction companies, digging began on both sides of Mont Blanc in 1959. Initially the cost of the effort was estimated at $16 million, but by the time it was concluded costs had escalated to more than $64 million, forcing considerable financial intervention on the part of both the French and Italian governments. Central to French financing was the work of Edmond Giscard d’Estaing, father of the French minister of finance.

Plans called for the tunnel to be 7.25 miles in length, with single lanes in each direction. It was to have an elaborate ventilation system placed beneath the roadway to ensure low levels of carbon monoxide, and it was to have a sophisticated electric lighting system. Thirty-four service stations were to be located approximately 1,000 yards apart to deal with emergency breakdowns and repairs. Consequently, more than 1.3 million cubic yards of rock had to be removed. Compared to New York City’s Holland tunnel, the Mont Blanc tunnel is four times longer, and it is designed to handle some 600,000 vehicles annually.

The Italian entrance to the Mont Blanc Tunnel.

The digging on both sides of the mountain was anything but routine during the next three years. Project engineers described the effort like a war, while workers maintained that the mountain was alive and that it fought back. Because Mont Blanc was formed with an upheaval from south to north that forced the harder material north, the Italians got the worst of the mountain geologically, as they had to deal with a soft claylike rock, which crumbled easily. The French had their own difficulties, however, as the tremendous weight of the mountain created such high pressures that the ceiling rock tended to explode. The French employed a huge drilling machine, named “Jumbo,” to simultaneously drill 140 holes 13 feet deep, thus enabling dynamite charges to be placed deep into the rock. The broken rock was then placed on a narrow-gauge railway and removed from the site. In contrast, the Italians used hand-held pneumatic drills and trucks to remove the waste. In the end, some five French workers died, along with four Italians. On the French side some ninety-nine days were lost to strikes, and French project-head André Gervais claimed the strikes were communist inspired.

Despite the difficulties, French and Italian workers met during the summer of 1962. Remarkably, the surveying of the tunnel was off just two inches horizontally and three inches vertically. Final work on the tunnel took three more years.


In addition to being the world’s longest tunnel and an engineering landmark, the Mont Blanc tunnel’s construction marked a signal achievement in post-World War II diplomatic and economic relations in Europe. Approximately one-third of Italy’s trade with Northern Europe passes through the tunnel. The project also marked a new era in common-market relations, quickening the pace of unity that had been envisioned with the signing of the Treaty of Rome in 1957.

Even with smooth operations overall, a deadly fire broke out in the tunnel on March 24, 1999, killing thirty-nine people. A flour and margarine truck from Belgium caught fire. The inferno that burned for more than two days released extremely toxic cyanide and carbon monoxide into the passageway. Because of the tunnel’s design, it acted like a giant chimney, sucking in air from the French side of the tunnel and moving the fumes to the Italian side.

After the Belgian truck tragedy in 1999, the tunnel was closed for three years while experts reconsidered its safety. The cause of the fire was never determined, although it could have been caused by a carelessly thrown cigarette or by poor vehicle maintenance. Whatever the case, the tunnel received a new safety passageway, closed-circuit cameras, fire-detection equipment, computer sensors, and a new fire station located at the middle of the tunnel. Increased safety came at a price—about $262 million—but the tunnel reopened March 9, 2002.

The fire also caught the attention of environmentalists, who began a campaign to close the tunnel. They argued that vehicle traffic, and especially lorries and their emissions, were degrading and destroying the natural areas around Mont Blanc. Other critics maintained that despite post-fire improvements, the tunnel remained a safety hazard and should be closed. To counter this criticism, authorities now monitor traffic closely, and fines from 90 to 750 Euros are imposed on those who are caught exceeding the conservative speed limit of 70 kilometers (about 45 miles) per hour. Tunnels Mont Blanc Tunnel

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">“Accidents: Mont Blanc Tunnel Fire May Have Killed 40: Damage Extent Still Unknown.” Engineering News-Record 242 (April 5, 1999): 26. An early engineering-profession report of the 1999 fire at the Mont Blanc tunnel.
  • citation-type="booksimple"

    xlink:type="simple">Davidson, Frank P., and Kathleen Lusk Brooke, comps. Building the World: An Encyclopedia of the Great Engineering Projects in History. 2 vols. Westport, Conn.: Greenwood Press, 2006. A study of the significant engineering projects from around the world. Volume two includes an entry on the Mont Blanc tunnel and cooperation between nations to build it.
  • citation-type="booksimple"

    xlink:type="simple">“Infrastructural Fires: Mont Blanc Tunnel, Italy.” www A thorough technical analysis of the 1999 tunnel fire.
  • citation-type="booksimple"

    xlink:type="simple">Pastore, Arthur Ralph. Dynamite Under the Alps: The Challenge of the Mont Blanc Tunnel. London: Chatto & Windus, 1967. An excellent overview of the tunnel project, easy to understand and detailed. Contains numerous photographs and diagrams of the project.
  • citation-type="booksimple"

    xlink:type="simple">“Tunnels: Mont Blanc Repairs Push Safety.” Engineering News-Record 246, no.7 (2001): 17. Describes the engineering and design remedies that addressed the fire and safety issues.
  • citation-type="booksimple"

    xlink:type="simple">Wechsberg, Joseph. “Reporter at Large: The Road Through Granite and Darkness.” New Yorker, May 18, 1963, 140-168. A well-written essay that focuses on André Gervais, the French construction boss.

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Categories: History