For thousands of years, Britain was an island cut off from the rest of Europe by a narrow stretch of water called the English Channel. To get to the mainland of Europe from the United Kingdom, travellers had to go down to the south coast and take a boat from one of the Channel ports.
The idea of building a bridge or digging a tunnel to link Britain with the rest of Europe had been in people's minds for centuries.
It would be a massive undertaking, but many people thought it could be done.
The narrowest strip of the English Channel is between Dover on the south coast of Britain and Sangatte on the north coast of France. These were the obvious points where the link should be made.
All the plans and projects to link Britain and France finally became a reality in 1994 with the opening of the Channel Tunnel. Now passengers could take a train from London to Europe and arrive in just a few hours.
The Channel Tunnel is really three tunnels, two for trains with a service tunnel in the middle. Each of the train tunnels only goes in one direction.