Post Historical Event stories, what is your world's first?

Everyone knows about our worlds 'first times', from the Rittenhouse square Santa Claus legend to the first electric light bulb by Edison. The inspiration for this thread comes from the first 'proof' of the earth being round, which was from 500BC by Pythagoras, and then 300BC Eratosthenes correctly calculated the length of the meridian running through Alexandria. <br><br>So what are your worlds 'first' stories, who was the first of your worlds to figure out if your world is round, what was the first war for, who was the first of your worlds to go into space, etc.<br><br><br>**TL;DR** What first stories happened on your world, be it who discovered round earth, who made the first electric light bulb, or the first war because of who ate the last cookie