Agricultural terracesSurplus foodInca RuinsResearchers15th centuryStill in use todayStone TerracesAgricultural terracesEcological zonesPisac RuinsInca TerracesStone TerracesTerraced LandscapeRuins and TerracesMicroclimatesCitadel at PisacSurrounded by mountainsInca wallArchwayInca Wall