Surtshellir, undoubtedly the most famous cave in Iceland. Right by the road just after it goes up onto the lava field. There are four openings, not all of a size for people to get through. The cave is 1970 m long, or 3500 m along with the cave Stefánshellir, which connects up to it, and with interesting side caves. Stone–built walls and bones have been found there. Outlawed thieves, called Hellismenn (“Cave men”), hid out in the caves in the 10th century, but were killed by farmers led by the chieftains of inland Borgarfjörður. According to Hellismanna saga the outlaws were sleeping in Vopnalág (“Weapon dell”) at the southern end of the Þorvaldsháls ridge when the farmers attacked them.