The world's first underwater tunnel is the Eurotunnel, also known as the Channel Tunnel, which connects Folkestone, Kent in England to Coquelles, Pas-de-Calais in France. The tunnel is 31.4 miles (50.5 km) long and runs beneath the English Channel, the body of water that separates England from France.
Construction on the tunnel began in 1988 and it was officially opened in 1994. It consists of three tunnels: two for trains and a smaller service tunnel. The two main tunnels were bored using a giant drilling machine, while the service tunnel was excavated using the "new Austrian tunneling method."
The Eurotunnel is used by both cars and trains. Cars are loaded onto trains and transported through the tunnel, while trains run on tracks within the tunnel. The journey through the tunnel by train takes about 35 minutes.
The Eurotunnel has had a significant impact on transportation between England and France. Prior to its construction, the only way to travel between the two countries was by ferry or by flying. The tunnel has greatly reduced travel time and made it much more convenient for people to travel between the two countries.
However, the Eurotunnel has had its share of problems. The project was plagued by cost overruns and construction delays, and it nearly went bankrupt shortly after it opened. Additionally, there have been several high-profile security breaches, with immigrants attempting to enter the UK by stowing away on trains. Despite these challenges, the Eurotunnel remains a significant engineering achievement and continues to be an important transportation link between England and France.