The Kiel Canal (currently known in German as the Nord-Ostsee-Kanal, and known up to 1948 as the Kaiser-Wilhelm-Kanal) was constructed between 1887 and 1895, and connects the North Sea at the mouth of the Elbe River near Brunsbüttel to the Baltic Sea at the Kiel Fjord. The photograph shows the construction of the lock in Kiel-Holtenau. This 100-km-long canal shortened the route from the North Sea to the Baltic by about 460 km. This man-made canal is one of the busiest waterways in the world in terms of shipping traffic.
The construction of the Kiel Canal: The huge Baltic Lock at Holtenau under construction, 1887–1895, photographer unknown; source: © IWM (HU 68385) http://www.iwm.org.uk/collections/item/object/205189290, IWM Non-Commercial Licence http://www.iwm.org.uk/corporate/privacy-copyright/licence.