Notes:
This story takes place on June 21st, mostly on an alternate Earth where young Bruce Wayne's parents are about to be murdered by Joe Chill. The Earth-One Batman's parents were murdered on June 26, exactly 20 years earlier, when Bruce was 8 years old. As Batman explains, the difference in dates is due to the five leap days that occurred during those two decades.
Fans have assigned this alternate Earth the designation "Earth-Five", however that name is not official.