Related by context. Frequent words. (Click for all words.) 70 cliff dwellings 63 Chaco Canyon 61 Anasazi 57 Inca Empire 55 lava tubes 55 Hohokam 54 petroglyphs 54 Canyon de Chelly 54 Sumerians 53 Mayan civilization 53 Inca empire 53 pictographs 52 Palaeolithic 52 Etruscans 52 royal tombs 52 prehistoric 52 Paiutes 51 landform 51 rock outcrops 51 middens 51 ancients 51 petroglyph 51 archaeological finds 51 Chiricahua 51 Tang Dynasty #-# 50 cairns 50 sagebrush habitat 50 adobe walls 50 limestone cave 50 Khazars 50 marine reptiles 50 pre Incan 50 Yuan Dynasty 50 Sassanid 50 ancient civilization 50 wigwams 50 Lascaux 50 archaeologically 50 limestone caves 50 Ming Dynasty #-# 50 archeological sites 50 henge 50 burial mounds 50 ancestors 49 Native Americans 49 Qing dynasties 49 landforms 49 Mesoamerican 49 classical antiquity 49 Thracians 49 obelisks 49 Harappan 49 ancient Hebrews 49 pre Columbian 49 Mesolithic 49 prehistory 49 inhabited 49 hunter gatherers 48 ancient civilizations 48 Mughal Empire 48 Painted Desert 48 Moravians 48 Omo River 48 Hasankeyf 48 barrens 48 Palenque 48 stupas 48 palisade 48 fourteenth century 48 ancient 48 cenotes 48 Fertile Crescent 48 stilt houses 48 sandstone cliffs 48 heiau 48 Beringia 48 neolithic 48 hieroglyphs 48 Spanish conquistadors 48 primitive tribes 48 primeval forest 48 Hopis 48 ancient Mesopotamia 48 Egyptian pyramids 48 Incas 48 Superstition Mountains 48 Koguryo 48 ancient Mayans 48 Cahokia Mounds 48 archaeological discoveries 48 Mesoamerica 48 artifacts 48 Harappa 48 Mycenaean 47 megalithic 47 Kumeyaay 47 Mormon pioneers 47 havelis 47 Dogon 47 megafauna 47 archeological digs