The Channel Tunnel, also known as the Chunnel, is a rail tunnel that connects the United Kingdom and France. It was opened in 1994 and is 31.4 miles long, making it the longest undersea tunnel in the world.

The construction of the Channel Tunnel began in 1988 and took six years to complete. The tunnel was constructed using two tunnel boring machines, one in the UK and one in France, which dug the tunnel from both sides until they met in the middle.

The Channel Tunnel has three tunnels, two of which are used for train transportation and one for ventilation and maintenance. Trains travel through the tunnel at speeds of up to 100 mph.

The Channel Tunnel has had a significant impact on transportation and trade between the UK and France. It has made travel between the two countries faster and easier, and has increased trade and economic relations.

The Channel Tunnel is also an engineering marvel and has won numerous awards for its design and construction. It was named one of the seven wonders of the modern world by the American Society of Civil Engineers.

Overall, the Channel Tunnel is an important landmark and a symbol of the close relationship between the UK and France.