Barcelona is the capital city of the autonomous community of Catalonia in the Kingdom of Spain, as well as the country's second most populous municipality, with a population of 1.6 million within city limits. Being the sixth-most populous urban area in the European Union after Paris, London, Madrid, the Ruhr area and Milan. It is the largest metropolis on the Mediterranean Sea, located on the coast between the mouths of the rivers Llobregat and Besòs, and bounded to the west by the Serra de Collserola mountain range, the tallest peak of which is 512 metres (1,680 feet) high.
It is a major cultural and economic centre in southwestern Europe. In 2008 it was the fourth most economically powerful city by GDP in the European Union and 35th in the world with GDP amounting to €177 billion. In 2012 Barcelona had a GDP of $170 billion; it is leading Spain in both employment rate and GDP per capita change. In 2009 the city was ranked Europe's third and one of the world’s most successful as a city brand. Since 2011 Barcelona has been a leading smart city in Europe. Barcelona is a transport hub, with the Port of Barcelona being one of Europe's principal seaports and busiest European passenger port, an international airport, Barcelona–El Prat Airport, which handles over 40 million passengers per year, an extensive motorway network, and a high-speed rail line with a link to France and the rest of Europe.
Barcelona has a rich cultural heritage and is today an important cultural centre and a major tourist destination. Particularly renowned are the architectural works of Antoni Gaudí and Lluís Domènech i Montaner, which have been designated UNESCO World Heritage Sites. The headquarters of the Union for the Mediterranean is located in Barcelona. The city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments. The city attractions include Barcelona Cathedral, Santa Maria del Mar, Parc de la Ciutadella, Casa Batlló, Palau Nacional, CaixaForum Barcelona, Magic Fountain of Montjuïc, Montjuïc Castle, Camp Nou, Palau de la Música Catalana, Tibidabo Amusement Park, Casa Milà, Park Güell, Sagrada Família, Barcelona Aquarium, Arc de Triomphe and many more.