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What event is being described...
I went to the door, and there I saw on the temple angels clothed in white covering the roof from end to end. They seemed to be walking to and fro; they appeared and disappeared. The third time they appeared and disappeared before I realized that they were not mortal men. Each time in a moment they vanished, and their reappearance was the same. This was in broad daylight, in the afternoon.
Prescinda Huntington describing the Kirtland Temple dedication