Located in the Hallmundarhraun lava field in West Iceland, this cave is a true natural wonder. This lava tube cave, formed around 1,100 years ago during a volcanic eruption, stretches an impressive 1,585 meters (5,200 feet), making it the largest known cave in Iceland. As you venture into Víðgelmir, you&rsquoll see magnificent rock formations lining the cave&rsquos walls. The cave&rsquos basaltic structure displays various colours and textures, providing a visual feast for explorers. One of the most captivating features within Víðgelmir is the presence of stunning ice stalactites and stalagmites formed over centuries by dripping water and freezing temperatures.