Touch the Eastern Crystal Pylon in Un'Goro Crater.
Discover and examine the Eastern Crystal Pylon
High up in the cliffs above me there is a large crystal pylon. Who placed it there, I cannot say, nor can I determine any reason that it would be built in such a strange place.
Maybe you can make more of it than I can. I personally don't care what it does, so you needn't report back to me, but perhaps one of the scholars in Marshal's Stand might be interested in what you discover.