Ischia is a volcanic island in the Tyrrhenian Sea, at the northern end of the Gulf of Naples. The roughly trapezoidal island lies c. 30 km from Naples and measures around 10 km east to west and 7 km north to south with a 34 km coastline and a surface area of 46.3 km². It is almost entirely mountainous, with the highest peak being volcanic Mount Epomeo at 788 meters: the volcano was active in Classical times. It has a population of over 60,000 people. Ischia Porto is the name of the main comune of the island. Other community areas include Barano d'Ischia, Casamicciola Terme, Forio, Lacco Ameno and Serrara Fontana. The main industry is tourism, centering on thermal spas that cater mostly to European (especially German) and Asian tourist clients eager to enjoy the fruits of the island's natural volcanic activity, its thermal hot springs, and its volcanic mud.