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
History of architecture most of the western length of the continent. Inca rope bridges could be considered the world's first suspension bridges. Because the Incas used no wheels (It would have been impractical for the terrain) or horses, they built their roads and bridges for foot and pack-llama traffic. Much of present-day architecture at the former Inca capital Cuzco shows both Incan and Spanish influences. The famous lost city Machu Picchu is the best surviving example of Incan architecture. Another significant site is Ollantaytambo. The Inca were sophisticated stone cutters whose masonry used no mortar. Inside what is the present-day United States, the