natural speleothem, cascades of lakes and waterfalls in nizhneshakuranskaya cave

abkhazia abstract adventure beautiful cascade cascades cave cavern caving dark exploration fantasy formation geology georgia grotto hole inside interior karst lakes landscape light limestone mineral mountain mystery natural nature nizhneshakuranskaya research rock south speleology speleothem stalactite stalactites stalagmite stalagmites stalagnate stone subterranean tourism travel tunnel underground water waterfall waterfalls yellow