These "buildings" are the remnants of a farm from the 17th century, which is still operating today, including a blacksmith forge, hay storage, and sheep stalls. Throughout the countryside we saw many buildings with these earthern roofs; in various stages of deterioration. Presumably the earth on the sides and roof provides insulation from the harsh Iceland winters. It was also very common to see these farms and homes tucked up under the face of the mountain; in a few places there were car-size boulders that had rolled down the mountain missing the homes - so far.