Having finished with the Seven Ancient Wonders of the World, the New Seven Wonders of the World and Seven Natural Wonders of the World, we now come to the Seven Modern Wonders of the World. These monumental engineering and construction feats of the 20th century include CN Tower, Itaipu Dam, Empire State Building, Golden Gate Bridge, Panama Canal, Channel Tunnel and Netherlands North Sea Protection Works.

Here we will discuss Channel Tunnel which links England with France and is the longest undersea tunnel in the world — 50 kilometres (31.35 miles) long, with 38 kilometres (24 miles) undersea. However, the Channel Tunnel is not the longest in terms of overall length as the Seikan Tunnel in Japan, linking Honshu and Hokkaido, is both longer overall at 53.85 kilometres (33.46 miles) and deeper at 240 metres (790 feet) below sea level.

The Channel Tunnel is a system of three tunnels that were bored at an average of 40 metres below seabed and the lowest point is 75 metres deep. Out of the three, two are unidirectional rail tunnels that are 7.6 metres in diameter and 30 metres apart, used for high-speed trains comprising passenger trains, trains that transport vehicles and international freight trains.

The south tunnel is used for trains moving from France to UK and the north tunnel is used for movement from UK to France.

The third tunnel is basically a service tunnel that connects the two train tunnels at every 375 metres and it is a road tunnel for maintenance and emergency vehicles and staff, as well as to be used as an escape in case of emergency in the main tunnels.

The Channel Tunnel officially opened on May 6, 1994. While construction for it had begun in 1988, the idea of such a tunnel was very old — in fact more than 200 years! It is said to have existed as early as 1802 when the French started to toy with the idea of digging a tunnel under the English Channel. Transportation in those days involved horse-drawn carriages so the plan involved a tunnel and two artificial islands in the sea so that horses could be refreshed.

But in those days, the British were very suspicious of any move of the French because their leader, Napoleon Bonaparte, was very notorious for waging wars. So the British just thought that this was just a plot to invade them and refused to even have a look at such a plan.

It was in 1974 that finally both the British and French governments sat down and planned such a project, however, progress halted again due to the huge budget needed for it, which was difficult for the British government that was going though tough economic times in those days.

Finally, with private funding, the project started in 1988 with ten contractors, 220 syndicate banks and 13,000 skilled and unskilled workers involved in it. Ten workers were killed during the construction.

The total cost of the project, when completed in 1994, was 4650 pounds, about 140 per cent more than the initial estimate.

All plans had to be in two languages — English and French. Construction, or rather digging, started on both sides of the English Channel at the same time, at Shakespeare Cliff near Dover, England and Sangatte, France. Huge boring machines dug and cut though the chalk under the sea, collected the debris and transported it back The service tunnel was completed first, on December 1, 1990, connecting Great Britain with mainland Europe for the first time, and rightly leading to a lot of celebration by the workers of the tunnel. On December 10, 1993, the first test run of the tunnel was done and it was officially opened on May 6, 1994, by Queen Elizabeth II and Francois Mitterrand, the then French president. The queen travelled in a Eurostar train through the tunnel to Calais, where she med President Mitterrand and an opening ceremony took place, after which the two travelled back for a similar ceremony on the British side at Folkestone. Over the years there have been accidents, fires and mishaps that have caused problems to and killed the passengers, something that had been feared from the beginning about this kind of a tunnel existing under the sea, miles from land. On November 18, 1996, a major fire broke out on a shuttle for heavy goods vehicle. Although there were no deaths, the tunnel was damaged considerably and it took six months for full operations to start again. Another fire that caused considerable damage to the tunnel was in August 2006, on a freight-carrying vehicle train going to France.

Breakdowns have also trapped passengers inside – in February 1996, some one thousand passengers were trapped inside the tunnel when two trains going to France broke down due to electronic circuit failure. Another electrical failure led passengers to remain trapped inside for more than six hours. But the biggest failure of trains inside the Channel Tunnel too place on December 18, 2009, during a very cold winter spell, trapping more than 2,000 passengers inside this time. The electrical failures due to melted snow seeping into the electronic systems were the cause and it was a major task to haul trains out of the tunnel.

An interesting fact about the tunnel project is that the spoil, or the chalk that was dug out from under the seabed. The quantity was simply enormous and putting it back into the sea would have lead to pollution of the water in the English Channel. The French simply dumped their spoil on land and created a landscaped hill for recreation. The British, always more thoughtful, first made a giant seawall of metal and concrete and then deposited the debris there. The whole pile was higher than sea level and it was turned into a seaside recreational zone of more than 73 acres. This shows that debris can come to much use if we care to put it to use!