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
Inca Trail to Machu Picchu this rule, permits can only be obtained through a government registered tour operator. All permits are paired with an individual passport, and are not transferable. The government monitors the trail closely; there are several control points along the trail. The Inca Trail elevation varies quite significantly and people often struggle with altitude sickness, especially if they have not spent much time in Cusco prior to trekking the trail. Cusco stands at 3,200 metres and is already significantly higher than Machu Picchu itself, however, many sections of the Inca Trail are much higher. Starting at 2,600 metres, the trail ascends to