De Inundation lock is part of the Stelling van Amsterdam and was laid by the War Department between 1890 and 1891. The lock was the key point in the reclamation of De Beemster and was set up with the purpose of “inundation of the polder De Beemster". It consists of a lock section in the dike body and a connected bowl section in the upper polder of De Beemster. By means of this bowl, water from the North Holland Canal was let into the polder. When, in 1940, the polder was flooded, it happened through this lock.