Elostirion

Elostirion is the tallest of the three towers that stood on the Tower Hills in Middle-Earth.

History of the Tower
Elostirion and two other unamed towers was built by Gil-galad who was the High King of the Elves in Middle-earth. The towers were built in honor of Elendil who came to Middle-Earth with sorrow and great loss. After that Elendil came often to the towers and soon he then put one of the palantíri of Arnor inside so people could look far beyond the sea. The tower Elostirion stood for many years after the death of Gil-galad and Elendil. Elostirion was soon under the care of Círdan and the Elves of Lindon.

Soon the palantíri in Elostirion was removed then put in the Blessed Realm at the time when Elrond and his company sailed away at the end of the Third Age.