Complex sentence: There were numerous supply bunkers, storage areas, barracks, hospitals, and command and control facilities., all concealed from aerial observation by an intricate system of natural and man-made camouflage that was constantly expanded and replaced.
Split into simpler sentences: There were numerous supply bunkers, storage areas, barracks, hospitals, and command and control facilities. All of this was concealed from aerial observation by an intricate system of natural and man-made camouflage that was constantly expanded and replaced.