About noon on May 9, 1780, day turned to night.
"It was very dark where I then was in New-Jersey; so much so that the fowls went to their roosts, the cocks crew and the whip-poor-wills sung their usual serenade; the people had to light candles in their houses to enable them to see to carry on their usual business; the night was as uncommonly dark as the day was," wrote Revolutionary War soldier Joseph Plumb Martin.
Across the states of New England and into Canada, darkness descended and remained until the middle of the next day.
Fearful persons believed the apocalypse was near.
Causes of the darkness have long been debated, but one accepted reason: A huge forest fire in what is now Algonquin Provincial Park. But, of course, with no modern communications, people knew nothing of this fire.