Spectacular images of lava flowing down the slopes of an erupting Mount Etna have drawn flocks of tourists to the Italian volcano – to the worry of local guides. The tallest active volcano in Europe, Etna has been spewing ash and lava for days, forcing the closure of the nearby Catania airport, a key gateway for tourists visiting the island of Sicily. Companies that organise nighttime hikes allowing participants to watch the eruption up close say they have been flooded with calls. “They all want...