Work on both sides of the English channel tunnel or Chunnel started in 1987. In French name is the Le tunnel sous la Manche and it's considered a wonder of the modern world. It's also on the list compiled by The American Society of Civil Engineers.
Path and Depth
The tunnel's path runs from Folkestone, Kent, near Dover in the United Kingdom to Coquelles, Pas-de-Calais, near Calais in northern France. At its lowest point, it's 246 to 250 feet deep. The tunnel averages 150 feet deep.
The Channel tunnel had been discussed for about a century, but in the 1980s the French and English government commissioned studies and chose a railway tunnel. The Lower Chalk was the most stable pathway because it was waterproof, and thick and stable enough, so they tunnelled through the chalk from both sides.
Dangers in the Tunnel
There was always fear of a build-up of car exhaust fumes, which is why the tunnel was built for trains. There already has been a disastrous fire in the tunnel in 2008.