© Joana Kruse/Alamy Images - 2025-09-07
rock natural landscape bedrock geological formation watercourse arch stream wilderness devil's bridge mountain river valley outcrop fluvial landforms of streams bryophyte geology nature reserve tourist attraction narrows river stream bed bridge ravine erosion arroyo boulder creek moss wadi arch bridge list of nonbuilding structure types riparian zone water feature fault valdivian temperate rain forest cliff national park canyon spring green algae stock photography