Mount Etna is an active stratovolcano on the east coast of Sicily, Italy, close to Messina and Catania. It lies above the convergent plate margin between the African Plate and the Eurasian Plate. It is the tallest active volcano on the European continent, currently 3,329 m (10,922 ft) high, though this varies with summit eruptions. It is the highest mountain in Italy south of the Alps. Etna covers an area of 1,190 km2 (459 sq mi) with a basal circumference of 140 km. This makes it by far the largest of the three active volcanoes in Italy, being about two and a half times the height of the next largest, Mount Vesuvius. Only Mount Teide in Tenerife surpasses it in the whole of the European–North-African region. In Greek Mythology, the deadly monster Typhon was trapped under this mountain by Zeus, the god of the sky and thunder and king of gods, and the forges of Hephaestus were said to also be located underneath it. Mount Etna is one of the most active volcanoes in the world and is in an almost constant state of activity. The fertile volcanic soils support extensive agriculture, with vineyards and orchards spread across the lower slopes of the mountain and the broad Plain of Catania to the south. Due to its history of recent activity and nearby population, Mount Etna has been designated a Decade Volcano by the United Nations. In June 2013, it was added to the list of UNESCO World Heritage Sites.