Barcelona is a city situated on the northeastern coast of Spain, positioned between the mouths of the Llobregat and Besòs rivers and bounded to the west by the Serra de Collserola mountain range. It serves as the capital and largest city of the autonomous community of Catalonia, as well as the second-most populous municipality in Spain after Madrid. The urban area extends into neighboring municipalities within the province of Barcelona, forming a significant metropolitan region that ranks among the largest on the Mediterranean Sea.