History of the North Sea the North Sea though they saw little action. The Austro-Prussian War (1866) resulted in Prussia's gaining full control of the Kiel Canal, allowing their Baltic ports access to the North Sea. France declared war on Prussia 19 July 1870 which initiated the Franco-Prussian War (1870–1871). The French Navy was, at the time far larger and superior to the North German Federal Navy, the Navy of the North German Confederation. Though the French did take a number of merchant ships bound to and from North Germany, shortages of manpower and coal, as well as conflicting orders, made the attempted blockade of
Baltic Sea depth is which is on the Swedish side of the center. The surface area is about and the volume is about . The periphery amounts to about of coastline. The Baltic Sea is one of the largest brackish inland seas by area, and occupies a basin (a "zungenbecken") formed by glacial erosion during the last few ice ages. Physical characteristics of the Baltic Sea, its main sub-regions, and the transition zone to the Skagerrak/North Sea area The International Hydrographic Organization defines the limits of the Baltic Sea as follows: The northern part of the Baltic Sea is known as the