"When gods war with gods, they use weapons we do not know. It was fire falling out of the sky and a mist that poisoned. It was the time of the Great Burning and the Destruction. They ran about like ants in the streets of their city—poor gods, poor gods!"
Benet's carefully constructed details concerning the Great Burning shown from John's point of view suggests that New York City was destroyed by a combination of air strikes and poisonous gas. Benet originally published the story in 1937, so he would have been extremely familiar with many of the dangerous weapons that debuted in World War I, like long range artillery shells and mustard gas.
Additionally, the Spanish Civil War had just occurred in 1936, only a year before the story's publication date, and could have served for inspiration in terms of "fire falling out of the sky," after the German's destructive air bombing of Guernica, Spain. The threat of potential weapons of capable of mass destruction loomed large and gives credence to Benet's portrayal of the end of modern civilization.