Forgotten remains of Europe's past never stops amazing me. It gives a reminder that over time, the borders in modern Europe have certainly not been where they are today. The conflicts during the last centuries have created, moved and removed borders and without knowledge of the past, things sometimes appear very strange at first sight.
The Masurian Canal was intended to connect the Great Masurian Lakes with the Baltic sea. It appears fairly logical that the isolated inner parts of East Prussia had poor communications with the rest of the German Empire and that a waterway would allow barges to transport supplies in and out.
The work with the canal finally began in 1911 but stopped with the outbreak of the First World War. The border changes as a result of the peace in 1918 created the isolated enclaves of Danzig and Köningsberg as the remains of the East Prussian part of Germany. A fair guess would have been that canals would have become obsolete as the rail network became denser, but the canal work was resumed in 1934. It appears quite obvious that this time, the canal project was more of a Keynesian way for the newly elected Hitler to create jobs and thereby gain stronger support in the poorer eastern provinces. It further appears like the canal project was not driven with the strongest determination so when WWII broke out and Germany's war effort required all resources it could get, the canal project was again suspended around 1940.
The map of post WWII Europe caused the far from finished canal to be split in half, where one part ended up in today's Poland and the other in today's Russian enclave of Kaliningrad. Most of the man-made parts of 50 km canal system is today completely overgrown, but a slightly bizarre set of remains is a series of ten giant concrete locks, designed to overcome the 110 m height difference between the Masurian Lakes and the Baltic sea.. The first two locks on the polish side appear to have had some usage modern times, but the rest stands as giant isolated monuments out in the middle of nowhere.