Vatnshellir Cave is one of Iceland's older lava tubes. Situated in the Snæfellsjökull National Park, the lava tube was created after a volcanic eruption over 8,000 years ago. The cave was created when molten rock started to cool down from the outside in and when draining out formed a hollow tube. Vatnshellir Cave can be easily accessed via an inbuilt stairway. Guided tours are strongly advised as the guides know the cave inside-out.