Númenor is J.R.R. Tolkien’s fictional island kingdom that sank at the end of the Second Age. It was created by the Valar for the Men who had helped the Elves during the wars against Morgoth.
The people of Númenor became powerful and long-lived, but their fear of death eventually turned into resentment of the immortal Elves and the Valar. Under the influence of Sauron, King Ar-Pharazôn attempted to challenge the divine powers. The island was destroyed in the Downfall of Númenor, and the world was changed from flat to round in Tolkien’s mythology.
Númenor is sometimes confused with Valinor, the blessed land sought by Ar-Pharazôn, or Beleriand, a region destroyed much earlier during the First Age. The story of Númenor is chiefly told in The Silmarillion and in related texts edited after Tolkien’s death.