Westerplatte monument, Gdaňsk, Poland 2014, in memory of the Polish defenders. A Monument of the Coast Defenders (Pomnik Obrońców Wybrzeża) was unveiled in 1966. Westerplatte is a peninsula in Gdańsk, Poland, located on the Baltic Sea coast mouth of the Dead Vistula (one of the Vistula delta estuaries), in the Gdańsk harbour channel. From 1926 to 1939 it was the location of a Polish Military Transit Depot (WST), sanctioned within the territory of the Free City of Danzig (now Gdańsk). It is famous for the Battle of Westerplatte, which was the first clash between Polish and German forces during the Invasion of Poland and thus the first battle of the European theater of World War II.