The jungle in the mountains was comprised of double and triple canopy tropical rainforest. It was often impossible to see the sun from the ground, and aerial observation could not detect even large enemy formations through the thick layers of foliage. These mountains are among the steepest in the world. It was up these mountains that infantrymen had to walk, day in, and day out, carrying 65-lb. rucksacks. Triple Canopy Rainforest