Many centuries before ‘going green’ became fashionable, Icelanders were constructing eco-friendly and energy efficient dwellings all over their island. Earth-sheltered houses have a long history that spans the globe from Africa to Europe. In Northern Europe evidence of turf houses (as they are known there) has been found as far back as the Iron Age. Later, the Romans used turf in the construction of their walls and fortresses in the northernmost reaches of their empire. It is believed that turf has been used for even longer than this, but as earth and grass rot away very easily, or become mixed with the surrounding environment, no traces of older constructions have yet been found.