Related by context. Frequent words. (Click for all words.) 46 forbidding terrain 45 unforgiving terrain 44 frozen wasteland 43 harsh climates 43 classical antiquity 42 colonial empires 42 temperate forests 42 sparsely inhabited 42 empires 41 Migrating birds 41 inconceivably 41 spacefaring 41 harsh winters 41 precipices 41 despotic rulers 41 invading armies 40 millenniums 40 Carthaginians 40 lunar poles 40 deserts 40 Thracians 40 despotic regimes 40 planet Krypton 40 Arabian desert 40 Terrans 40 habitable planet 40 Kalahari desert 40 saber toothed tigers 40 cold winters 40 lava tubes 39 robotic probes 39 taiga 39 mythically 39 subarctic 39 Hitler armies 39 frigid winters 39 winters 39 climes 39 mythologies 39 Egyptian pyramids 39 vast expanses 39 faraway 39 subfreezing 39 Earthlike 39 landmass 39 frigid 39 Aztec empire 39 Martian rocks 39 moon Europa 39 Byzantine Empire 39 fantastical creatures 38 outer planets 38 Inca Empire 38 temperate zones 38 grassy plains 38 explorers 38 Goldilocks zone 38 Beringia 38 Soviet Union disintegrated 38 unimaginably 38 mine sweepers 38 inhospitable 38 arctic tundra 38 landmasses 38 lush jungles 38 tundra 38 desert sands 38 incalculably 38 icecap 38 frozen tundra 38 steppes 38 medieval castles 38 lightless 38 Pan Arabism 38 potentially habitable 38 winged creature 37 heavily cratered 37 Arctic archipelago 37 Lake Vostok 37 lifeforms 37 Dark Continent 37 coastland 37 nomads 37 marine reptiles 37 Persian empire 37 desolate landscape 37 Communist regimes 37 interplanetary spacecraft 37 Spanish conquistadors 37 Northrend 37 civilization 37 metropolises 37 terra incognita 37 Arctic Circle 37 armies 37 adventurers 37 baobab tree 37 warmer wetter 37 Byzantines 37 erupting volcanoes 37 cave dweller