"Raufarholshellir lava tube cave is one of the better known lava caves in Iceland and it is easily accessible. The length of the tube is estimated to be 1360 metres. There are four entrances, all in easy reach of each other. The cave is partially collapsed and is difficult to trek, except for the innermost part which is easier because little has broken from the ceiling.
During the winter time a lot of ice forms in the forward section of the cave and almost every stone is coated with a thin crust of ice, which makes it hazardous to walk around the cave.
In the backward section, the cave forks into 3 tunnels, the lava flow from those tunnels probably joined in the Raufarholshellir cave 5000 years ago. Lava falls and other spectacular lava formations can be seen deep in those tunnels."