Dry stone from the arable or cultural land. They serve both as cattle/sheep fences and the lot's borders. Sometimes also the dry stone terracing is apparent, often combined with parts of stone masonry (house foundations and shed walls) that are held together by a clay-cum-needles "composite" mortar. In Peru in the 15th century AD, the Inca made use of otherwise unusable slopes by building dry stone walls to create terraces. They also employed this mode of construction for freestanding walls. Their ashlar type construction in Machu Picchu uses the classic Inca architectural style of polished dry-stone walls of regular shape. The Incas
Lost City of the Kalahari Clement had found a geological curiosity, dating back 180 million years to the great upheaval accompanying the birth of the Drakensberg Mountains in South Africa. The stones are composed of dolerite, a particular type of igneous rock which can erode to give the appearance of straight and regular blocks suggesting artificial construction. On 27 January 2016, the Travel Channel aired an episode of "Expedition Unknown" called "Kalahari Desert's Lost City", in which the host, Josh Gates, found man-made walls and rocks with art work in an area that matched Farini's description of the Lost City. Lost City of the Kalahari