The Fehmarnbelt tunnel linking Denmark and Germany will be the world's longest immersed tunnel, with completion expected in 2029

At 17 kilometers long, the Fehmarnbelt tunnel will become the longest road and rail tunnel in the world, cutting the journey between Denmark and Germany to just seven minutes. Construction started in 2020 and significant progress is being made, including the completion of the land sections. The project, described as a "masterpiece of engineering", will create a vital link between Scandinavia and continental Europe and is Denmark's largest infrastructure project.