Andenes were stone-retained agricultural terraces cut into steep Andean slopes, with engineered fills of stone, gravel and topsoil and integral irrigation channels. Developed over millennia and elaborated by the Inca, they converted near-vertical terrain into stable, drained, frost-buffered cropland and checked erosion across whole valleys. Sites such as Moray and the terraces at Pisac and Ollantaytambo show terracing organised at landscape scale. The fills' drainage and thermal mass let cultivation climb thousands of metres up the cordillera.
Terracing was the foundation of Andean food security and made dense highland settlement and the Inca state possible. It remains a textbook case of landform-led, erosion-controlling agricultural engineering.