Lake Peipus Lake Peipus Lake Peipus (; ; ) is the largest transboundary lake in Europe, lies on the border between Estonia and Russia. The lake is the fifth-largest in Europe after Lake Ladoga and Lake Onega (in Russia north of St. Petersburg), Lake Vänern (in Sweden), and Lake Saimaa (in Finland). Lake Peipus represents a remnant of a body of water which existed in this area during an Ice Age. It covers , and has an average depth of , the deepest point being . The lake has several islands and consists of 3 parts: The lake is used for fishing
Finnish Ladoga Naval Detachment group was the icebreaker "Aallokas", whose commander Captain-Lieutenant Asikainen also commanded the gunboats. There were no major naval battles in the open waters of Lake Ladoga during 1939 - 1940, so the fleet units were tasked with fire support against the attacking Red Army, and spreading mines along the coastal areas. By January 1940 the ice became so thick that only "Aallokas" could be used, and she was damaged in an attack by Soviet aircraft on February 2. After the peace on March 13 the Finnish vessels had to be left at Ladoga, which had become a Soviet lake. Some