The North Sea invites to many discoveries. It is bounded by the island of Great Britain in the west and the northern and the central Europe continent with Norway, Denmark, Germany, Netherlands, Belgium and France. In the southwest the North Sea leads through the Strait of Dover into the English Channel, in the east it has contact with the Baltic Sea through Skagerrak and Kattegat and to the north it opens like a funnel to the North Atlantic. The North Sea itself is an important trade route and serves Central and Northern Europe as a way to world markets. The southern North Sea, together with the adjacent English Channel, the most densely trafficked shipping region in the world. The main inflows are the Scheldt, the Meuse, the Rhine, the Ems, the Weser, the Elbe and the Thames. The surface area of the North Sea is around 575,000 square kilometers at an average depth of 94 meters, which is a water volume of about 54,000 km.