 The connection between Peberholm and the artificial peninsula at Kastrup on Amager island, the nearest populated part of Denmark, is through the long Drogden Tunnel ("Drogdentunnelen").It comprises a immersed tube plus entry tunnels at each end.The tube tunnel is made from 20 prefabricated reinforced concrete segments – the largest in the world at 55,000 tonnes each – interconnected in a trench dug in the seabed.