A set of musical horns present in the mythology of J.R.R. Tolkien, particularly The Silmarillion.
The Ulumúri were made from white shell by a Maia called Salmar, for the sea-dwelling Vala Ulmo. Nobody who hears the music of these horns can forget it. Such a person will long for the sea the rest of his life, even if he feared the sea before.
When the Vanyar and Noldor came to sea separating the land that would later be called Beleriand from Aman, Ulmo used the Ulumúri along with words to make them desire the sea rather than fear it. Ulmo and his servants then uprooted an island, which they used like a ship to take the Vanyar and Noldor to Aman. A piece of the island broke off and became the Isle of Balar.
Informational and geographical references:
Tolkien, J.R.R. The Silmarillion. New York: Ballantine Books, 1979.
Day, David. Tolkien: The Illustrated Encyclopedia. New York: Macmillan Publishing Company, 1991.