Barcelona is a city and metropolis in Spain. It's 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. Its metropolitan area extends beyond the administrative city limits with a population of around 4.7 million people, being the sixth-most populous urban area in the European Union after Paris, London, Madrid, the Ruhr area and Milan. It is considered as the largest metropolis on the Mediterranean Sea. The city is located on the coast on the Mediterranean Sea between the mouths of the rivers Llobregat and Besòs, and it's bounded to the west by the Serra de Collserola mountain range, the tallest peak of which is 512 meters high.
Madrid is the capital city of the Kingdom of Spain and the largest municipality in both the Community of Madrid and Spain as a whole. The city has a population of almost 3.2 million with a metropolitan area population of approximately 6.5 million. It is the third-largest city in the European Union (EU) after London and Berlin, and its metropolitan area is the third-largest in the EU after those of London and Paris. The municipality itself covers an area of 604.3 km2 (233.3 sq mi).