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
PeruRail which boasts a series of five switchbacks called locally 'El Zig-Zag', which enable the train to climb up the steep incline out of Cusco, before it can begin its descent to the Sacred Valley of the Incas and then continue down to Machu Picchu. However, this section of the route is currently suspended, and all trains to Machu Picchu leave from Poroy, just outside Cusco, instead. From Poroy, the narrow-gauge line goes northwest to Ollantaytambo, where the branch from Urubamba joins, then on to Machu Picchu station in Aguas Calientes. Tracks formerly continued into the jungle, but they were destroyed