The Battle of Westerplatte was the first battle of the German invasion of Poland, marking the start of World War II in Europe. It occurred on the Westerplatte peninsula in the harbour of the Free City of Danzig (now Gdańsk, Poland). In the mid-1920s, the Second Polish Republic established the Polish Military Transit Depot (, WST) on the Westerplatte peninsula in the Free City of Danzig. Beginning on 1 September 1939, the German Wehrmacht and Danzig Police assaulted the WST. Despite initial assessment on both sides that the Polish garrison might hold out for several hours before being reinforced or overwhelmed, the Poles held out for seven days and repelled thirteen assaults that included dive-bomber attacks and naval shelling. The defence of the Westerplatte was an inspiration for the Polish Army and people in the face of German advances elsewhere and is still regarded as a symbol of resistance in modern Poland. The Polish government is planning to open a dedicated public museum on the site in 2026. Background Westerplatte is a peninsula in the Bay of Gdańsk, which in 1939 was known as the Bay of Danzig. Following the re-establishment of Polish independence after World War I, much of the surrounding region became part of Poland. The city of Danzig (now Gdańsk, Poland), historically an important port city, became an independent city-state, the Free City of Danzig. The Free City was nominally supervised by the League of Nations but Danzig became increasingly allied with Germany, reflecting its predominantly ethnic German population. In 1921, in the wake of the Polish-Soviet War, the League of Nations granted Poland the right to install a garrisoned ammunition depot near Danzig. Despite objections from the Free City, this right was confirmed in 1925, and an area of was selected on the Westerplatte peninsula. Westerplatte was separated from the New Port of Danzig mainly by the harbour channel; on land, the Polish-held part of Westerplatte was separated from Danzig's territory by a brick wall topped with barbed wire. A dedicated rail line, passing through the Free City, connected the depot with nearby Polish territory. The depot, referred to in League documents as the (WST) (), was completed in November 1925, officially transferred to Poland on the last day of that year, and became operational shortly after in January 1926, with 22 active storage warehouses. The Polish garrison's complement was set at 2 officers, 20 NCOs,