The city's speedy urban growth, especially since the 1960s, has filled the entire Aburrá Valley and made towns touch its borders: Bello, Copacabana, Girardota, Barbosa, Envigado, Itagüí, San Antonio de Prado, La Estrella, Sabaneta and Caldas, among others. With the growth of the city placing Medellín among the most economically important cities in the nation, local leaders were compelled to view the city as a complex, urban system comparable to other industrialized cities in the world, rather than as a provincial town.