Underground spaces and cavernous recesses have been used and adapted to serve as places of religious worship since the beginnings of civilization. In the 13th century, if not before, the making of both cave and monolithic churches was developed in Ethiopia. The Ethiopian monolith is unique to Christian religious architecture anywhere in the world. It is in Ethiopia, and only there, that the craft of hewing churches from the rock survives to the present day, but only just. It is known that a very small number of Ethiopian craftsman are engaged in perpetuating this activity using ancient methods and hand tools but, following the social and economic changes introduced by the Derg in 1974, and the surge in availability of hydro-electric power from the recently built dam over the Takazze river (and soon the Nile), both the craftsman and their hand-held hammers and chisels lie on the verge of extinction.