Video: How the tunnel elements are connected
When the elements have to be lowered to the seabed, it is the culmination of several weeks of preparation. A standard element weighs 73,500 tonnes and is 217 meters long. Therefore, the immersion requires a specially built vessel that can place the element with a few millimeters of precision on the seabed.
This animation shows how the tunnel's elements are connected on the seabed.