Bucharest is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, at, on the banks of the Dâmbovița River, less than north of the Danube River and the Bulgarian border. Bucharest was first mentioned in documents in 1459. It became the capital of Romania in 1862 and is the centre of Romanian media, culture, and art. Its architecture is a mix of historical, interbellum, communist-era and modern. In the period between the two World Wars, the citys elegant architecture and the sophistication of its elite earned Bucharest the nickname of "Little Paris" . According to the 2011 census, 1,883,425 inhabitants live within the city limits, According to unofficial data, the population is more than 3 million. Bucharest is the sixth-largest city in the European Union by population within city limits, after London, Berlin, Madrid, Rome, and Paris. Economically, Bucharest is the most prosperous city in Romania and is one of the main industrial centres and transportation hubs of Eastern Europe. The city has big convention facilities, educational institutes, cultural venues, traditional "shopping arcades", and recreational areas. The city proper is administratively known as the "Municipality of Bucharest", and has the same administrative level as that of a national county, being further subdivided into six sectors, each governed by a local mayor.