The Pelóri were the mountain-fence of Aman, raised by the Valar to defend against the evils of Melkor after he destroyed their original dwelling-place at Almaren. The highest peak of the Pelóri was Taniquetil, on which were the mansions of Manwë and Varda.
They were the tallest of all mountains, and the tallest of the Pelóri was Taniquetil, on which stood the high mansions of Manwë and Varda. Behind them to the West, the Light of the Trees shone, but the narrow shores beneath their eastern feet were in darkness.
When the Eldar came to Aman, the Valar cut a rift in the Mountains, the Calacirya, to let the Light shine through them. In that pass, the Vanyar and the Noldor built the city of Tirion, and the Pass of Light looked out onto the Bay of Eldamar and lit the isle of Tol Eressëa, where the Teleri dwelt in those ancient days.