The Metropolitan Area of Barcelona (AMB) is the public administration of the metropolitan area of Barcelona, which occupies 636 km² and is made up with 36 municipalities with more than 3.2 million inhabitants. AMB management areas are related to territory and urban planning, mobility, housing, environment economic development and social cohesion. The metropolitan area is the largest metropolitan conurbation in the western Mediterranean, which generates half of the GDP in Catalonia.