Ключевые слова: aerial, aerial view, background, biosphere, bulgaria, clouds, cloudscape, destination, drone, environment, europe, fog, green, hill, kyustendil region, lake, landmark, landscape, mountain, mountain lakes, mountaineering, nature, outdoor, recreation, reflection, reserves, rila, rila lakes, rila mountains, rock, route, scenery, seven rila lakes, sight, sightseeing, sun, sunny, the lower, the seven rila lakes, tourism, trail, travel, trip, vacation, view, water,