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 Lost city A lost city is a settlement that fell into terminal decline and became extensively or completely uninhabited, with the consequence that the site's former significance was no longer known to the wider world. The locations of many lost cities have been forgotten, but some have been rediscovered and studied extensively by scientists. Recently abandoned cities or cities whose location was never in question might be referred to as ruins or ghost towns. The search for such lost cities by European explorers and adventurers in Africa, the Americas, and Southeast Asia from the 15th century onwards eventually led to