'Darkness' in the Bible

It will be a day of dreadful darkness, a day of foreboding storm clouds, like blackness spread over the mountains. It is a huge and powerful army -- there has never been anything like it ever before, and there will not be anything like it for many generations to come!

The sunlight will be turned to darkness and the moon to the color of blood, before the day of the Lord comes -- that great and terrible day!