Before World War II saw the historical region of Masuria in East Prussia fall into Polish hands, German engineers had long dreamt of building a canal to connect the Great Masurian Lakes to the Baltic Sea. Construction of the Masurian Canal eventually began in 1911 but was interrupted by war and political turmoil in Germany—until the war put an end to the project, seemingly for good. Today, the canal’s partially completed locks are scattered across northern Poland and Russia’s Kaliningrad oblast, with the most impressive ruins located near the Polish village…