Stralsund remained under Swedish control until the Battle of Stralsund (1807), when Napoleon Bonaparte's army occupied it. Seized by Ferdinand von Schill's freikorps in 1809, it subsequently reverted to French control, with Schill killed in action. With the Congress of Vienna (1815), Stralsund became a part of the Prussian Province of Pomerania and the seat of a government region resembling the former Swedish Pomerania. Following the First World War Stralsund suffered the same sort of political unrest and unemployment that afflicted much of Germany. In May 1919 Stralsund workers clashed with police, and martial law was declared. In the early 1920s the Independent Social Democratic Party (USPD) became the strongest party in Stralsund, but its political fortunes waned rapidly, and in September 1922 it reunited with the Social Democratic Party (SPD). In the national parliamentary election of May 1924, the conservative German National People's Party (DNVP) polled 8,547 votes in Stralsund, the SPD 3,534, the Communists 1,825 and the German People's Party (DVP) of Foreign Minister Gustav Stresemann 1,417. However, in keeping with national trends, Hitler's National Socialists made rapid gains in the late 1920s, and by the time of the last free national election in July 1932 the Nazis polled twice as many votes in Stralsund as the SPD. During the Nazi period (1933–1945), Stralsund's military installations expanded, and a naval training base opened on the nearby island of Dänholm. In World War II the city was subjected to repeated Allied bombing. Attacks by the U.S. Army Air Forces in 1944 killed some 800 Stralsunders and destroyed an estimated 8,000 dwellings. The 354th Rifle Division of the Red Army occupied Stralsund on April 28, 1945 – 10 days before the end of the war in Europe. Approximately half its population had fled. During the period of the German Democratic Republic (GDR), Stralsund saw the construction of numerous Plattenbau prefabricated apartment blocks. Its economic life centered on the now state-owned shipyard, which largely focussed on building ships for the Soviet Union. After German reunification in 1990, the city's historic old town was thoroughly restored, and Communist-era apartment blocks were renovated and upgraded. In 2002 the old towns of Stralsund and Wismar, some 120 km to the west, were listed as UNESCO World Heritage Sites. Stralsund's shipyard was privatized, and thereafter specialized in constructing container ships. Culture and sights Main sights The historic Stralsund old town island is a UNESCO World