important commercial canal (canals and inland waterways) in western Germany linking the Ruhr industrial area with the North Sea near Emden. The canal was opened in 1899 and is about 269 km (167 miles) long. It extends from Dortmund, its southern terminus, to meet the Rhine-Herne Canal at Henrichenburg. At that point there is a complex of two boat lifts and two locks, built between 1899 and 1989 to accommodate increasing traffic and boat size. Just north of Henrichenburg, it is joined by the Wesel-Datteln and the Datteln-Hamm canals. These connections provide links between the Rhine River and the North Sea entirely within German territory. It then runs northeast and north together with the Mittelland Canal, which provides links to the Elbe and northeast Germany, joining it to the north of Münster, and from Papenburg the canal runs through the canalized bed of the Ems River to reach the North Sea. Chief imports passing southward are iron ore, grain, and sugar; products sent downstream (northward) include coal, coke, stone, and gravel. Some 13 million tons pass through the lock at Münster annually.