only town on the small Isola di San Pietro (area 20 sq mi 【52 sq km】), just off the southwest coast of Sardinia, Italy. The town was named after Charles Emmanuel III of Savoy, who resettled the island in 1738, after centuries of desertion, with Genoese fugitives from the North African island of Tabarka. It has an observatory, set up in 1899 by the International Geodetic Survey as one of the six special latitude observatories on the parallel 39°08′ N. Steamers ply between Porto Vesme (on Sardinia) and the island of Sant'Antioco. The main industry is tunny fishing; salt extraction and manganese mining are also carried on. Pop. (2006 est.) mun., 6,466.