The great tower of the haven of Avallónë on the island Tol Eressëa; said to be the first sight a mariner would see when approaching the Undying Lands. In the days when those lands were still present in the world, it was said that the sharp-eyed could see Avallónë and its tower from the island of Númenor to the east, but the Ban of the Valar prevented the Númenorëans from ever sailing to the haven.

When Ar-Pharazôn ultimately broke the Ban, the kingdom of Númenor was destroyed and the Undying Lands - including Tol Eressëa and its haven - were taken away from the Circles of the World. The Tower, however, held the Masterstone of the palantíri, so that certain other Seeing-stones could still glimpse it along the Straight Road. In particular, the Seeing-stone of Emyn Beraid was said to have been used by Elendil to gaze across the Great Sea into the lost West.