A final riddle that bears on Elrond's House in Rivendell is yet to be solved.
'You have proven yourself an expert riddle-solver. Bilbo and I have, of late, been contemplating a riddle of the most interesting sort -- one for which no answer is yet known. This riddle seems to bear upon the lineage of the House of Elrond itself and may be of great import if it is solved.
'For once, we cannot say for sure that the answer truly lies in Imladris, but it is certain that the riddle is concerned with Rivendell more than with any other place.
'Bilbo can tell you more, but I think for the full story of this riddle you will have to speak with others as well.'
Bilbo is standing with Lindir in the Hall of Fire in the Last Homely House.
Lindir told you to speak with Bilbo to learn the unsolved riddle.
Elrond is in his library in the Last Homely House.
Bilbo believes Elrond may know more about the riddle.
The jewel of the moon,
Enshrined in the water,
From mother to daughter
Is given a boon.
Ships sail to the west,
Forgetting all sorrow,
Landfall on the morrow,
The isles of the blest.
Glorfindel is outside the house of Elrond, by the waterfall.
Elrond has directed you to speak to Glorfindel about the riddle.
The jewel of the moon,
Enshrined in the water,
From mother to daughter
Is given a boon.
Ships sail to the west,
Forgetting all sorrow,
Landfall on the morrow,
The isles of the blest.