3 Nephi 8:23

And it came to pass that it did last for the space of three days, that there was no light seen; and there was great mourning, and howling, and weeping among all the people continually; yea, great were the groanings of the people, because of the darkness and the great destruction which had come upon them.

The darkness lasted for three days. There was no light at all. All the people cried and wailed without stopping. They were very sad because of the darkness and all the destruction.

The darkness lasted three days. No light anywhere. The people mourned and wept and howled without stopping. Their groaning was terrible because of the darkness and the destruction that had come.