What’s in a day? It depends more than ever on which day it is. Most days in themselves resemble each other, but Oct. 29, 1929; Dec. 7, 1941; Nov. 22, 1963; and Sept. 11, 2001, stand out from the rest in their Quotient of Horror, in the suddenness with which they came, sundering the present from past.

Who ever had dreamed that the market would crash? That American land would be bombed by an enemy power in a sneak attack? That another American president would be killed just like Abraham Lincoln? Or that everyday aircraft would be used to rain fire down from the skies?