The others cast themselves down upon the fragrant grass, but Frodo stood awhile still lost in wonder. It seemed to him that he had stepped through a high window that looked on a vanished world. A light was upon it for which his language had no name. All that he saw was shapely, but the shapes seemed at once clear cut, as if they had been first conceived and drawn at the uncovering of his eyes, and ancient as if they had endured for ever. He saw no colour but those he knew, gold and white and blue and green, but they were fresh and poignant, as if he had at that moment first perceived them and made for them names new and wonderful. In winter here no heart could mourn for summer or for spring. No blemish or sickness or deformity could be seen in anything that grew upon the earth. On the land of Lórien there was no stain.

Drawing a deep breath they passed inside. In a few steps they were in utter and impenetrable dark. Not since the lightless passages of Moria had Frodo or Sam known such darkness, and if possible here it was deeper and denser. There, there were airs moving, and echoes, and a sense of space. Here the air was still, stagnant, heavy, and sound fell dead. They walked as it were in a black vapour wrought of veritable darkness itself that, as it was breathed, brought blindness not only to the eyes but to the mind, so that even the memory of colours and of forms and of any light faded out of thought. Night always had been, and always would be, and night was all.

isn't it odd that he doesn't remember that the giant spiders put their victims to sleep rather than killing them outright?