4. A Darkening Fog
One-upping the three-day blackout that was Egypt’s ninth plague is the blanket of fog that covered most of the world. The mystifying brume darkened the Middle East, parts of Asia, and Europe for a total of 18 months.
Many researchers have pointed to a volcanic eruption in Iceland that erupted in 536, whose ashes could have spread across the Northern Hemisphere contributing to the gloaming fog.