The fertile volcanic soils produced from this activity support extensive agriculture, with vineyards and orchards spread across the lower slopes of the mountain and the broad Plain of Catania to the south.

[10] Due to its history of recent activity and nearby population, Mount Etna has been designated a Decade Volcano by the United Nations.

What were originally Welsh conceptions concerning a dwarf king of a paradisal, Celtic underworld became attached to the quasi-historic figure of Arthur as "Ruler of the Antipodes" and were then transplanted into a Sicilian milieu, by Bretons impressed by the already otherworldly associations of the great, volcanic mountain of their new home.

Mediaevalist Roger Sherman Loomis quotes passages from the works of Gervase of Tilbury and Caesarius of Heisterbach (dating from the late twelfth century) featuring accounts of Arthur's returning of a lost horse which had strayed into his subterranean kingdom beneath Etna.

Caesarius quotes as his authority for the story a certain canon Godescalcus of Bonn, who considered it a matter of historical fact of the time of Emperor Henry's conquest of Sicily circa 1194.

[17][18][19] The Fada de Gibel of the Castle of Gibaldar (Fairy of Etna) appears in Jaufre, the only surviving Arthurian romance in the Occitan language, the composition of which is dated to between 1180 and 1230.

[20] Another Sicilian conception of the fairy realm or castle of Morgan le Fay is the Fata Morgana, an optical phenomenon common in the Strait of Messina.

Volcanic activity first took place at Etna about 500,000 years ago, with eruptions occurring beneath the sea off the ancient coastline of Sicily.

From about 35,000 to 15,000 years ago, Etna experienced some highly explosive eruptions, generating large pyroclastic flows, which left extensive ignimbrite deposits.

Thousands of years ago, the eastern flank of the mountain experienced a catastrophic collapse, generating an enormous landslide in an event similar to that seen in the 1980 eruption of Mount St. Helens.

Research published in 2006 suggested this occurred around 8,000 years ago, and caused a huge tsunami, which left its mark in several places in the eastern Mediterranean.

This caldera has been almost entirely filled by subsequent lava eruptions but is still visible as a distinct break in the slope of the mountain near the base of the present-day summit cone.

Mount Etna is moving towards the Mediterranean Sea at an average rate of 14 mm (0.55 in) per year, the massif sliding on an unconsolidated layer above the older sloping terrain.

[26] A particularly violent explosive (Plinian) summit eruption occurred in 122 BCE, and caused heavy tephra falls to the southeast, including the town of Catania, where many roofs collapsed.

[27] To help with reconstruction after the devastating effects of the eruption, the Roman government exempted the population of Catania from paying taxes for ten years.

[29] During the first 1500 years CE, many eruptions went unrecorded (or records have been lost); among the more significant are: (1) an eruption in about 1030 CE near Monte Ilice on the lower southeast flank, which produced a lava flow that travelled about 10 km, reaching the sea north of Acireale; the villages of Santa Tecla and Stazzo are built on the broad delta built by this lava flow into the sea;[30] (2) an eruption in about 1160 (or 1224), from a fissure at only 350–450 m (1,148–1,476 ft) elevation on the south-southeast flank near the village of Mascalucia, whose lava flow reached the sea just to the north of Catania, in the area now occupied by the portion of the city named Ognina.

[32] The 1669 eruption, Etna's most destructive since 122 BCE, started on 11 March 1669 and produced lava flows that destroyed at least 10 villages on its southern flank before reaching the city walls of the town of Catania five weeks later, on 15 April.

A small portion of lava eventually broke through a fragile section of the city walls on the western side of Catania and destroyed a few buildings before stopping in the rear of the Benedictine monastery, without reaching the centre of the town.

Contrary to widespread reports of up to 15,000 (or even 20,000) human fatalities caused by the lava,[33] contemporaneous accounts written both in Italian and English[34] mention no deaths related to the 1669 eruption (but give very precise figures of the number of buildings destroyed, the area of cultivated land lost, and the economic damage).

The third and most vigorous of these fissures opened late on 4 November at an unusually low elevation, approximately 1,200 m (3,937 ft) above sea-level, in a zone known as Ripe della Naca.

In March 1981, the town of Randazzo on the northwestern flank of Etna narrowly escaped destruction by unusually fast-moving lava flows.

In 2002–2003, a much larger eruption threw up a huge column of ash that could easily be seen from space and fell as far away as Libya, 600 km (370 mi) south across the Mediterranean Sea.

Footage from the eruptions was recorded by Lucasfilm and integrated into the landscape of the planet Mustafar in the 2005 film Star Wars: Episode III – Revenge of the Sith.

Following a slow and non-destructive lava outflow on the upper southeastern flank between September 2004 and March 2005, intense eruptions occurred at the Southeast Crater in July–December 2006.

[43][44][45][46][47][48] The July 2011 episode also endangered the Sapienza Refuge, the main tourist hub on the volcano, but the lava flow was successfully diverted.

[50][51] The activity continued on the following days, with an ash plume that reached 7 km (23,000 ft) in height that forced Catania airport to shut down for a few hours.

[53] An eruption on 16 March 2017 injured 10 people, including a BBC News television crew, after magma exploded upon contact with snow.

[54][55] An eruption on 24 December 2018, following a dyke intrusion at shallow depth, spewed ash into the air, forcing the closure of airspace around Mount Etna.

[56][57] Beginning in February 2021, Mount Etna began a series of explosive eruptions, which have had an impact on nearby villages and cities, with volcanic ash and rock falling as far away as Catania.

[73] The borders of ten municipalities (Adrano, Biancavilla, Belpasso, Bronte (from two sides), Castiglione di Sicilia, Maletto, Nicolosi, Randazzo, Sant'Alfio, Zafferana Etnea) meet on the summit of Mount Etna, making this a multipoint of elevenfold complexity.