Greifswald is located in the remote northern frontier of Germany, but it used to be in the political center: since the 3rd century, it has become the "Lufthansa Alliance", a commercial and political alliance between cities in northern Germany, together with Hamburg, Bremen and Rostock. However, in the14th and15th centuries, the gray eves Wald port could not meet the needs of economic development at that time, and the city lagged behind other allied cities. However, the Baltic Sea, shipping and traditional ports still give the city a unique atmosphere, and the Baltic Sea is also the favorite leisure place for college students today.