Space shuttle on the background of the earth's surfaceSpace shuttle on the background of the earth's surface
Reflection of clouds, mountain peaks and trees in the surface of the lake on a windless dayReflection of clouds, mountain peaks and trees in the surface of the lake on a windless day
Landscape of the long bridge at sunset over the water surfaceLandscape of the long bridge at sunset over the water surface
В математике: граница, отделяющая геометрическое тело от внешнего пространства. Наружная сторона чего-н..