The 31-mile Channel Tunnel
(Chunnel) fulfilled a centuries-old dream by linking Britain and the rest of Europe. More than a tunnel, it combines infrastructure and immense machinery in an underwater system of unprecedented ambition. Three 5-feet thick concrete tubes plunge into the earth at Coquelles, France, and burrow through the chalky basement of the English Channel. They reemerge behind the white cliffs of Dover at Folkstone.
Through two of the tubes rush the broadest trains ever built. The double decker behemoths, which span 14-feet across, traverse the tunnel at close to 100 mph. Passengers board not on foot, but in automobiles and buses. Maintenance and emergency vehicles utilize the third tunnel, located between the rail tubes.
Huge pistons open and close ducts, relieving the pressure that builds ahead of the trains' noses. Some 300 miles of cold water piping run alongside the rail tracks to drain off the heat raised by the air friction.
Return to the Seven Wonders of the Modern World directory