Utrecht is the fourth-largest city and a municipality of the Netherlands, capital and with a population of around 360’000 (as of 2021) the most populous city of the province of Utrecht. It is located in the eastern corner of the Randstad conurbation, in the very centre of mainland Netherlands. Utrecht's ancient city centre features many buildings and structures, several dating as far back as the High Middle Ages (AD 1000 to around 1250). It has been the religious centre of the Netherlands since the 8th century and was the most important city in the Netherlands until the Dutch Golden Age (1588 to 1672), when it was surpassed by Amsterdam as the country's cultural centre and most populous city. The city is host to Utrecht University, the largest university in the Netherlands, as well as several other institutions of higher education. Due to its central position within the country, it is an important transport hub for both rail and road transport. It contains the busiest train station in the Netherlands, Utrecht Centraal and has the second-highest number of cultural events in the Netherlands, after Amsterdam. When the main flow of the Rhine moved south during the past centuries, the old bed which still flowed through the heart of the town became ever more canalized; and the wharf system was built as an inner city harbour system.