Kiel canal, linking the North Sea to the Baltic, from Brunsbüttle to Kiel, was opened in 1895 by Wilhelm II. It is 100 km long, and over 38,000 ships use it each year. The Holtenau locks let it be linked to the Baltic. On the locks island an interactive exhibition presents a model of the canal and locks. Among the constructions allowing the canal to be crossed, see Rendsburg rail viaduct, that of Grünental and of Hochdonn.