This can be without doubt called an ‘engineering miracle’. Denmark and Sweden are divided by the Baltic Sea, but this posed no problem for the ingenious engineers of the Oresung bridge. They managed to connect the Danish capital of Copenhagen to the Swedish city of Malmo via a roadway that turns into a bridge! Danish architect George K. S. Rotne designed the amazing multi-structure which stretches about 8km before transitioning through an artificial island into a 4km tunnel under Flint Channel. The bridge opened in 2000 and of the concrete tunnel was cast on land and towed out to the location.
Transitions thru artificial island