Ключевые слова: background, bulgaria, canyon, clouds, environment, erma, erma river, erma river gorge, europe, forest, geology, gorge, greben, greben mountain, green, hill, landmark, landscape, mountain, mountaineering, nature, outdoor, pernik region, recreation, river, rocks, route, ruy, ruy mountain, scenery, sight, sightseeing, stone, summer, tourism, trail, tran, tran gorge, travel, trees, trip, vacation, view, water,