Surtshellir is a lava cave located in western Iceland, around 60 km from the settlement of Borgarnes. Approximately a mile in length, it is the longest such cave in the country. While mentioned in the medieval historical-geographical work Landnámabók, Eggert Ólafsson was the first to give a thorough documentation of the cave in his 1750 travels of the region.[1] It is named after the fire giantSurtr, a prominent figure in Norse mythology, who is prophesied to one day engulf the world in the fire of his flaming sword.[2][3]