Related by context. Frequent words. (Click for all words.) 63 Inca Empire 60 Andean highlands 58 highlands 58 pre Incan 57 Lambayeque 57 Tiwanaku 56 Mesoamerica 55 limestone caves 55 Olmecs 54 Fertile Crescent 54 montane 54 Palaeolithic 54 highland 54 Chihuahuan Desert 54 Andes Mountains 54 Alentejo 53 Tapajos 53 evergreen forests 53 Caral 53 Sierra Madre mountains 53 Tarim Basin 53 Amazonian rainforest 53 Yungas 53 Chaco Canyon 53 grassy plains 53 Amazon basin 53 deciduous forests 52 Incas 52 Madre de Dios 52 conifer forests 52 Ucayali 52 radiocarbon dated 52 coniferous forests 52 salars 52 extinct volcanoes 52 Huancavelica 52 Spanish conquerors 51 indigenous cultures 51 arid 51 fertile plains 51 Sierra Madre Mountains 51 landforms 51 Incan 51 rock outcrops 51 teosinte 51 Peruvian Andes 51 Omo River 51 river valleys 51 ancient Mesopotamia 51 Mesoamerican 51 alluvial deposits 51 limestone cave 51 fluvial 50 Guajira 50 fossil specimens 50 Bighorn Basin 50 Harappan 50 Thar Desert 50 pottery fragments 50 Sierra Madres 50 semiarid 50 biodiversity hotspot 50 Inca ruins 50 loess 50 volcanic peaks 50 deltaic 50 prehistoric 50 Santa Rosalia 50 pre Columbian 50 cerrado 50 Lake Atitlan 50 arid plains 50 La Guajira 50 semi arid 50 adobes 50 temperate rainforest 50 volcanic soils 49 cenotes 49 Harappa 49 Inca empire 49 Huichol 49 pictographs 49 Paracas 49 Cerro Rico 49 Cerrado 49 adobe brick 49 prehistory 49 indigenous tribes 49 Dong Son 49 lowland 49 Anasazi 49 sparsely inhabited 49 mountainous 49 Neolithic 49 Peruvian Amazon 49 faunal 49 irrigated agriculture 49 ancient kingdoms 49 Andes 49 Atapuerca 49 Late Triassic