Songhellir is a famous cave, known for its echoes. The name means the cave of songs.
On the walls of the cave, a lot of people have written their names, some of them very well known persons in Iceland. Among them are for example Eggert Olafsson and Bjarni Palsson who were by the end of 18th century travelling around their own country - quite an enterprise at the time - fighting against superstition and for Enlightenment. You may also find there runes and signs of sorcery.