Swallowed By Darkness
"As their eyes became used to the dimness they could see a little way to either side in a sort of darkened green glimmer. Occasionally a slender beam of sun that had the luck to slip in through some opening in the leaves far above, and still more luck in not being caught in the tangled boughs and matted twigs beneath, stabbed down thin and bright before them. But this was seldom, and it soon ceased altogether.
But they had to go on and on, long after they were sick for the sight of the sun and of the sky, and longed for the feel of wind on their faces. There was no movement of air down under the forest-roof, and it was everlastingly still and dark and stuffy. They felt as if they were being slowly suffocated."
JRR Tolkien, "the Hobbit"