The Chunnel

Connecting England and France, the Chunnel runs underneath which body of water?

And the answer: The English Channel.

Short for the Channel Tunnel, the Chunnel runs underneath the narrowest part of the English Channel. Both passenger and freight trains use the tunnel, taking just a half hour to travel the 31.5 miles. The Chunnel is the only fixed link between the island of Great Britain and the European mainland.

Photo credit: Denis Charlet / AFP/ Getty Images. 

Situated between some of the most powerful European nations, the English Channel has long been one of the world's most important maritime passages. However, rocky shores and unpredictable weather made travel along the Channel challenging and, at times, dangerous. Engineers proposed ideas to bridge the 33-kilometer gap since the early 1800s, including proposals for artificial islands linked by bridges and submerged tubes suspended by floating platforms. Yet it was ultimately the idea of a long, underwater tunnel – it would be longer than any other in the world –  that piqued European interest.

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At first, the idea of such a long underwater tunnel seemed impossible. Besides the pressure of the water above, carving a deep passage through solid rock would be incredibly dangerous and expensive for all involved. The project required the invention of the tunnel boring machine, a piece of equipment that had its prototype debut in the creation of the London Tube System but was not fully developed until 1845. What's more: the United Kingdom viewed their geographic isolation as an advantage, fearing the increased feasibility of attack from European mainland countries. As such, proposals to connect the countries were squashed until the late 20th century.

With the discovery of a solid layer of rock beneath the English Channel, proposals for the Chunnel gained strength and support. And, since the rise of air warfare, the argument for UK isolation seemed more and more obsolete. In 1985, an agreement was reached. A group of French and British companies invested the modern-day equivalent of 14 billion pounds in the creation of the underwater tunnel, making it the most expensive infrastructure project of the time.

The project called for three tunnels: one to get to France, one to get to England, and a smaller service tunnel below them both. In addition, crossover chambers, air ducts and emergency passages all needed to be built. This amounted to an intended 200 kilometers of tunnels, all in the underwater stretch of 33 kilometers. The project ultimately employed over 13,000 workers, and cost the lives of 10 individuals. It was dangerous, uncertain work, but after two and a half years of digging, the tunnel was complete – and for the first time since the Ice Age, workers reached European mainland on foot.

To learn more about this incredible feat of human engineering, check out the video below.    

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