The vast black-lava sand flats of Mýrdalssandur, east of Vík, are formed from material washed out from underneath Mýrdalsjökull during Katla eruptions. This 700-sq-km desert is bleak and desolate (some say haunted), but rather awe-inspiring. It looks lifeless, but Arctic foxes and seabirds can be spied here.
South of Rte 1, the small peak of Hjörleifshöfði (221m) rises above the sands and offers good views towards Vestmannaeyjar. On the other side of Rte 1, the green hill of Hafursey (582m) is another option for walks from Vík.