The North Sea is part of the Atlantic Ocean on the European continental shelf. It is bordered by the countries of Norway, Denmark, Germany, Netherlands, Belgium, France, England and Scotland. It connects to the Atlantic through the Dover Straight and English Channel to the south and the Norwegian Sea in the north. The North Sea is the most heavily trafficked sea in the world, and European trade and economics depend on it heavily. Its strategic importance has been exploited since the Roman and Viking times.