The B-10, also known as Ronda Litoral (Catalan: [ˈrɔndə lituˈɾal], Spanish: [ˈronda litoˈɾal]; English: Coastal Ring Road), is a 20-kilometre (12.43 mi) freeway in Catalonia, Spain partially encircling Barcelona passing through the eastern side of the city. It starts at Nus de la Trinitat interchange in northern Barcelona and runs along the entire length of the Besòs River and the city's coastline south to Nus del Llobregat interchange in Barcelona's southern suburbs, where it becomes the Autovía A-2. Both north and south end interchanges link the freeway to the B-20 or Ronda de Dalt, which encircles Barcelona passing through the western side, jointly forming a beltway commonly referred to as the rondes that surrounds the city.