Together with the cities of Espoo, Vantaa and Kauniainen—and surrounding commuter towns, including the neighbouring municipality of Sipoo to the east—Helsinki forms a metropolitan area. This area is often considered Finland's only metropolis and is the world's northernmost metropolitan area with over one million inhabitants. Additionally, it is the northernmost capital of an EU member state. Helsinki is the third-largest municipality in the Nordic countries, after Stockholm and Oslo. Its urban area is the third-largest in the Nordic countries, after Stockholm and Copenhagen. Helsinki Airport, in the neighbouring city of Vantaa, serves the city with frequent flights to numerous destinations in Europe, North America, and Asia.