I don't do tunnels ... and am wary of bridges - so, don't think I will be travelling on this -
The bridge (or should it be called tunnel) goes under water to allow movement of ships . In order for ships to pass, this bridge is half under the water. You drive down in the water and then come out on the other side. Truly a marvelous piece of engineering! This bridge is between Sweden and Denmark. The picture was taken from the Sweden side.