Ключевые слова: aerial, aerial view, balkans, bulgaria, canyon, dam, drone, engineering, environment, erma, erma river, europe, fishing, forest, geological, hill, hydro, hydroelectricity, landmark, landscape, meander, mountain, natural, nature, panorama, pernik, pernik region, power, radomir, relax, resource, river, ruy, ruy mountain, scenics, serbia, sight, sightseeing, terrain, tourism, tran, travel, tree, view, water, wilderness, yarlovtsi,