Apennines (ăpˈənĪnz) [key], Ital. Appennino, mountain system, running the entire length of the Italian peninsula. It extends south c.840 mi (1,350 km) from the Cadibona Pass in Liguria, NW Italy, where the Apennines join with the Ligurian Alps, to the Strait of Messina; the mountains of Sicily are a southwest continuation of the system. The Apennines are widest (c.80 mi/130 km) in the central section, which also contains the highest peaks, Mt. Corno (9,560 ft/2,914 m high) and Mt. Amaro (9,170 ft/2,795 m high). However, in general the peaks are much lower. The central and southern Apennines have mineral springs, crater lakes, fumaroles, and volcanoes (two, Vesuvius and Etna, are still active). The southern section also experiences many earthquakes. In 1980 one near Campania left 4800 people dead. Of the many rivers rising in the Apennines, the few important ones (Arno, Tiber, and Volturno) all flow W into the Tyrrhenian Sea. The N and central Apennines are rich in a great variety of minerals. There are many hydroelectric plants in the mountains. The once heavily forested slopes of the system have been greatly reduced by humans through the centuries; attempts at conservation and reforestation have been made. The greatest population concentrations are found in the valleys and the fertile basins. Extensive pasturelands are used for sheep and goat grazing. The Apennines are pierced by many railroad tunnels and highway passes, and by the Appian, Cassian, Flaminian, and Salarian ways (see Roman roads).