thumb|right|Hellnahellir Hellnahellir () is the largest man-made or artificial cave in Iceland. It is located in Landsveit, South Iceland. The cave is almost long and the walls are covered with engravings. Its age is unknown but it is most probably from 12th or 13th century.
2 mapped locations
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).