スルツヘトリル

right|thumb|One of four entrances to the Surtshellir lava tube in the Hallmundarhraun lava field. right|thumb|Looking up towards the fourth (lowest and farthest west) entrance to Surtshellir, seen from within the section of the cave called Íshellir (ice-cave). The white slab is ice, which was preserved into summertime. thumb|Typical passage shapes in the Surtshellir-Stefanshellir lava tube system, showing intact walls and pahoehoe floors Surtshellir () is a lava cave located in western Iceland, around 60 km from the settlement of Borgarnes. Approximately a mile in length, it is one of the