The city is the second largest in the country with a population of approximately 640,000 inhabitants in the municipality and about 2.3 million inhabitants in the shared metropolitan area of The Hague and Rotterdam MRDH. Rotterdam is a vibrant, multicultural city; it is known for its university (Erasmus), cutting-edge architecture, lively cultural life, industrial riverside setting, its maritime heritage and colourful summer events. The municipality stretches all the way to the North Sea with gigantic areas like Europoort and Maasvlakte 1&2. All belong to the Port of Rotterdam.Starting as a dam constructed in 1270 on the Rotte River, Rotterdam has grown into a major international commercial centre. The port of Rotterdam is Europe's busiest port by cargo tonnage, and was the world's busiest from 1962 until it was surpassed by Shanghai in 2004. Rotterdam's commercial and strategic importance is based on its location near the mouth of the Nieuwe Maas (New Meuse), a channel in the delta formed by the Rhine and Meuse on the North Sea. These rivers lead directly into the centre of Europe, including the industrial Ruhr region, which is why Rotterdam is often called the "Gateway to Europe"