Related by context. Frequent words. (Click for all words.) 56 craters 56 gully 55 riverbed 54 drainage ditches 54 boulders 53 crevasses 53 ridges 52 ruts 52 steep slopes 51 ravines 51 mountain slopes 50 hillsides 50 potholes 49 footpaths 49 riverbanks 49 drainages 49 embankments 48 crater 48 rock formations 48 cliffs 48 lava flows 47 slopes 47 Martian surface 47 ditches 47 sinkholes 47 slope 47 mountainsides 47 creeks 46 gorges 46 outcrops 46 undergrowth 46 lava 46 sandbars 46 depressions 46 sand dunes 46 escarpment 46 meadows 46 volcanic rock 46 creek bed 45 crevices 45 dunes 45 pavements 45 vegetation 45 valleys 45 creek 45 culverts 44 ponds 44 retaining walls 44 tree trunks 44 sandy 44 puddles 44 hillside 44 hollows 44 silt 44 footpath 44 canyons 43 rutted 43 landslides 43 glaciers 43 catch basins 43 hills 43 grassed 43 mangroves 43 canals 43 drainage 43 canyon 43 rocks 43 mounds 42 sediment 42 humps 42 divots 42 ridge 42 rocky terrain 42 dune 42 comets 42 steep slope 42 roadbed 42 driveways 42 roads 42 gutters 41 soil erosion 41 overgrowth 41 irrigation canals 41 sand dune 41 subsurface 41 outcrop 41 roadsides 41 glacier 41 sloping 41 storm drains 41 caverns 41 basalt 41 mountain ranges 41 sedimentation 41 ledges 41 willows 41 outcropping 41 dense forests 40 hedgerows 40 topsoil 40 sloped