caverns, stalagmites, grottoes, tunnels, stalactites, mountains, burrows, crevices, carlsbad caverns, tadpole shrimp, waterfalls, glowworms, crevasses, hallstatt, karst, hibernaculum, quarries, passageways, crags, valleys, jungles, hideout, tombs, hyraxes, spelunkers, pictographs, sarcophaguses, gorges, lairs, refugium, hot springs, igloos, tarns, spelunking, forts, cellars, huts, cenote, cirques, yetis, catacombs, abysses, fossils, dens, precipices, prehistoric, hideaways, eskers, sanctuaries, tidepool, cavelike, toltecs, olduvai gorge, hermitage, lascaux, lakes, volcanic crater, coelacanths, cave dweller, canyon, postholes, monasteries, cliffs, ledges, seacoasts, outcroppings, landforms, himalayas, trilobites, fumaroles, anthills, eyries, knolls, alcoves, labyrinths, kiva, carpathian mountains, middens, neolithic age, lodges, castle, temples, adobes, tufa, potsherds, mountainside, escarpments, dinos, rivers, wilderness, peccary, massifs, huaca, palisades, paleolithic age, creatures, lanternfish, habitats, glacial boulder, cappadocia, volcanoes, highlands, cave, cavern, grotto, grottos, canyons, aqueducts, waterways, creeks, pools, beaches, mines

., brown bat, cave, cave myotis, cliff dweller, eyeless, hibernate, myotis velifer, ossiferous, potholer, rock kangaroo, rock wallaby, rout, rout out, rupestral, spelaeologist, spelaeology, speleologist, speleology, spelunk, spelunker, troll, unfathomed