The association of Calais with the powerful port city took place in June 25 of 1964.
The exchanges between the two twin towns concern mainly education, sports and culture.
Duisburg is also the city where the Eurorock festival was born in 1992.
The city located in the Rhineland of the North-Westphalia has more than 504,000 inhabitants. It possesses the biggest river port in Europe and the largest innner port in the world.
As Düsseldorf, Duisburg hosts the Deutsche Oper am Rhein, one of the major operas in Germany.