The Rhine River flows from the Swiss Alps, through Germany and the Netherlands, to the North Sea. It is one of the longest and most important rivers in Europe, historically a source of transport, trade and defence. Today, the Rhine continues to be a major focus of industry, trade and tourism in Germany.
The Rhine is the longest river in Germany, although there is some confusion as to its actual length. In 1932, the German encyclopedia Knaurs Lexikon printed its length as 1,320 kilometres (820 miles), and that has been the generally accepted figure. Early in 2010, however, a scientist researching ecological aspects of the Rhine noticed that in publications prior to 1932, the Rhine was measured at 1,230 kilometres, or 765 miles. The Local, an English-language German newspaper, reports that new measurements support the revised length, although current sources often still cite the 1,320km figure.
The Rhine originates in the Swiss Alps and flows north to form the Swiss-Austrian border. It turns west at Lake Constance and flows along the border between Germany and Switzerland, an area marked by waterfalls and rapids. The Rhine turns back northward at Basel, Switzerland, forming part of the German-French border between the Vosges Mountains on the French side and the Black Forest in southwestern Germany. Further north, the middle Rhine cuts a deep gorge between the Hunsrück and Taunus Mountains until below Bonn, where the landscape flattens out and the river flows by Cologne and Düsseldorf. After reaching the Netherlands the Rhine joins several other rivers to form one of the largest river deltas in western Europe. To prevent flooding the Netherlands completed the Delta Project in 1986, redirecting the Rhine and other rivers to the North Sea via dams and channels.
The Romans thought of the Rhine as the outermost limits of civilisation; classical Latin texts describe the area beyond as wilderness inhabited by primitive tribes. The first settlement along the Rhine was founded near modern-day Cologne in 38BC by a Germanic tribe called the Ubii. It became a Roman city around AD50, and Roman artefacts can still be found along Cologne's riverbanks. The river was vital to trade and exploration in classical and medieval times. In 1815, the Congress of Vienna agreed upon free navigation of the Rhine, which removed toll bridges and paved the way for modern industrial and commercial use.
International conflict surrounded the Rhine for centuries. French leaders from Louis XIV to Napoleon tried to extend France's borders by annexing land west of the Rhine. After World War I, Allied forces occupied an area along the river including the Luxembourg, Belgium and Dutch borders. The Treaty of Versailles in 1919 allowed Belgium to annex certain areas of the Rhineland traditionally German in language and culture. The river was also a major defensive line during World War II.
The Rhine's long history as a means of border defence has left its banks littered with ruins and spectacular castles. The 90-mile gorge of the middle Rhine, in particular, is famous for its fortresses, castles and vineyards, and is a centre for tourism. Tourists also flock to cities along the river: Cologne and Dusseldorf in Germany and Strasbourg in France.