The monumental locks have been designed in 1729 by civil engineer Willem Loré. Three canals meet here: Dokkumer Grootdiep, the Zwemmer and the Zijlsterrijd. New locks were build in 1969, when the sea arm Lauwerszee was changed into a lake by building dikes around it. Since then these locks are not used for passing of ships anymore. Photo's taken on may 23, 2010.