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...