With nearly thirty thousand inhabitants, Carbonia is the ninth largest Sardinian town and the most highly-populated in the Sulcis area. It features wide, tree-lined roads: a 45-metre high bell-tower rises above the houses, alongside the granite and trachyte façade of the church of San Ponziano. The city was established in 1938 and was built in just two years, to guarantee accommodation to the workers of the Sirai-Serbariu coalfield. The mines in the Sulcis area were one of the main sources of Italy's supply of energy at that time. Its origin is shown in the name Carbonia (carbone is the Italian word for coal): it was built next to the large mine, replacing a nineteenth century village and incorporating it as a district. The basin, which was active between 1937 and 1964, had nine wells and one hundred kilometres of tunnels. Miners were recruited from all over Italy, to extract the coal, and there were immediately 16 thousand residing in Carbonia, while the peak was in 1949 with 48 thousand residents and 60 thousand people living there.