Stralsund has one of the best natural harbors in the Baltic. The town is separated from the island of Rügen by a narrow sea channel, the Strait of Bodden, and makes its living mainly from shipyards, fishing fleets, and, to an increasing degree, tourism. Stralsund boasts a picturesque network of canals, coves, and lakes, as well as more half-timbered 19th-century houses and a more intact sense of history than many other cities on Germany's Baltic coast. During the 1200s, it was rivaled in the Hanseatic League only by Lübeck and enjoyed a rich trade with many of the other cities around the Baltic basin. Perhaps because of its success, the town has been invaded repeatedly throughout its long history, by armies from Denmark, Sweden, Holland, Napoleonic France, Prussia, and, in May 1945, the Soviet Union. By the mid-1960s, much of the inner core of Stralsund had been faithfully rebuilt by the Communist local government, though some historic structures remain. Many visitors use Stralsund as the takeoff point for the flat and sandy Baltic island of Rügen, which is joined to Stralsund by a 2km (1 1/4-mile) bridge.