Grábrókarhraun, a rough lava–field about 3,000 years old, covered with moss and birch bushes. The lava came from three craters, Grábrók, which is the largest, Grá­brókarfell, and a small crater that has been more or less dug up and used as gravel for the road. There is an excellent view from the top of Grábrók.