Related by context. Frequent words. (Click for all words.) 59 cliff dwellings 58 Chaco Canyon 55 relict 55 Inca Empire 55 Petroglyphs 54 landform 53 kiva 53 lava tubes 53 inhabitation 53 Anasazi 52 rock outcrops 52 erosional 52 Olmecs 52 radiocarbon dates 51 sandstone formations 51 Upper Paleolithic 51 adobes 51 ancient kingdoms 51 archaeologically 51 montane 51 stelae 51 Harappan 51 extinct volcanoes 51 Palaeolithic 51 Sassanid 51 pre Incan 51 calcareous 51 coquina 51 Mesoamerican 51 granite cliffs 50 petroglyph 50 Knossos 50 megalithic 50 Stupa 50 limestone caves 50 archeological sites 50 acropolis 50 middens 50 Durrington Walls 49 stupas 49 megaliths 49 sandstone cliffs 49 bamboo groves 49 limestone cave 49 prehistoric 49 burial mounds 49 ancient 49 Incan 49 Caral 49 Sierra Madre Mountains 49 pictographs 49 zonation 49 stone carvings 49 Excavated 49 Tikal 49 volcanic peaks 49 landforms 49 archeological digs 48 prehistory 48 grassy meadows 48 limestone formations 48 adobe brick 48 escarpments 48 grottos 48 Chihuahuan Desert 48 Tenochtitlan 48 Pictish 48 flora fauna 48 Egyptian pyramids 48 petroglyphs 48 Long Term Ecological 48 Egyptian pharaohs 48 Jinsha 48 cypress swamp 48 Meroe 48 conifer forests 48 palisade 48 Valles Marineris 48 henge 47 vernacular architecture 47 archeological 47 astronomical observatory 47 Inca empire 47 massif 47 Ecological Reserve 47 evergreen forests 47 Elamite 47 mosaic floors 47 grassy plains 47 Neolithic 47 refugia 47 Lascaux 47 volcanic cones 47 Tiwanaku 47 Atapuerca 47 radiocarbon dated 47 knolls 47 Shang Dynasty 47 lava tube 47 preserved fossils 47 outcroppings