landslides

The Incas were accomplished engineers who built long-lasting structures, from Machu Pichu on a ridgetop to the Inca Road system along the spine of the Andes Mountains. A sculpted landscape masterpiece that is less well known is a set of large circular depressions lined with concentric rings of stone-lined terraces. Named Moray and located on a high plain about 20 miles northwest of Cusco, these circles began as deep natural sinkholes with unstable slopes at the angle of repose.