The Fehmarn Belt Fixed Link, an underwater tunnel poised to link the Danish island of Lolland with Germany's Fehmarn island, represents a remarkable feat of engineering. This remarkable tunnel beneath the Baltic Sea, set to become one of the planet's longest submerged structures, is due for completion by 2029. Spanning more than 18 kilometres (11 miles), the Fehmarnbelt tunnel will dramatically reduce journey times between Scandinavia and mainland Europe. Danish planning firm Femern has