Related by context. Frequent words. (Click for all words.) 71 Paleolithic 67 Neolithic 66 Pleistocene 65 Neandertals 62 Bronze Age 61 prehistoric 61 Pliocene 60 Neanderthals 60 hunter gatherers 60 prehistory 59 Middle Ages 59 Eocene 59 Iron Age 57 Cretaceous 57 Neanderthal 57 Archaic 56 Hellenistic 56 Homo sapiens 55 fifteenth century 55 Triassic 55 Precambrian 55 #BC [003] 55 Little Ice Age 54 glaciation 54 #th century 54 hunter gatherer 54 megafauna 54 hominids 54 millennium BC 53 Ordovician 53 Han Dynasty 53 nineteenth century 53 radiocarbon dating 52 Australopithecus 52 Holocene 52 seventeenth century 52 mammoths 52 Paleozoic 52 fossils 52 Jurassic 52 Homo erectus 52 Mesozoic 51 theropods 51 eighteenth century 51 hominid 51 Mesoamerica 51 twentieth century 50 radiocarbon 50 Stone Age 50 Industrial Revolution 50 Prehistoric 49 Proterozoic 49 Cro Magnon 49 sixteenth century 48 primitive 48 Mesoamerican 48 pre Columbian 48 dinosaurs 48 Paleo 48 Archaeopteryx 48 Ice Age 48 sauropod 48 fossil 48 volcanism 48 epochs 48 Olmec 47 Miocene 47 Roman Empire 47 ancient civilization 47 ancient 47 Pharaonic 47 ancient Egyptians 47 burial mounds 47 antiquity 47 woolly mammoths 47 #BC [002] 47 ancestors 47 mediaeval 47 ancients 47 dinosaur fossils 47 Oetzi 46 sauropods 46 paleo 46 domestication 46 #AD [002] 46 millennia 46 Medieval 46 millenniums 46 Anthropologists 46 ancient civilizations 46 medieval 45 ca. 45 anthropological 45 palaeontologists 45 Sumerian 45 arrowheads 45 Nineteenth Century 45 Anasazi 45 Byzantine Empire 45 mastodons 45 civilization