Foursquare Lock in Emden in the state of Lower Saxony. The lock with a central chamber is unique in Europe. It connects four waterways: the Ems-Jade-Canal, the moat of Emden, the creek of Fehntje and the Red Sluice. These generally have different water levels. The lock is also the intersection of four districts of Emden: Wolthusen, Herrento, Klein-Faldern and Gross-Faldern