The Zuiderzee Works (Dutch: Zuiderzeewerken) is a man-made system of dams and dikes, land reclamation and water drainage work, in total the largest hydraulic engineering project undertaken by the Netherlands during the twentieth century. The project involved the damming of the Zuiderzee, a large, shallow inlet of the North Sea, and the reclamation of land in the newly enclosed water using polders. Its main purposes are to improve flood protection and create additional land for agriculture.