Mount Etna in Sicily, the most active stratovolcano in the world
Background
The UNESCO World Heritage Centre describes Mount Etna as "an iconic site encompassing 19,237 uninhabited hectares on the highest part of Mount Etna, on the eastern coast of Sicily" and states that "Mount Etna is the highest Mediterranean island mountain and the most active stratovolcano in the world." The inscribed property measures 19,237 ha and "forms part of the Parco dell'Etna Regional Nature Park". Under criterion (viii) the Centre calls Etna "one of the world's most active and iconic volcanoes, and an outstanding example of ongoing geological processes and volcanic landforms". Its activity "has been documented by humans for at least 2,700 years - making it one of the world's longest documented records of historical volcanism". Etna was inscribed on the World Heritage List in 2013, with reference number 1427, and is one of Italy's natural properties.
In plain words
Stratovolcano — A steep, cone-shaped volcano built up from many layers of lava and ash.