The moment during world war one, when German and French soldiers met in the nowhere land between their trenches to play soccer. No war for about an hour. Hugging, appreciation on both sides for each other, singing Christmas carols.
This moment shows, that people don't want to fight, they're made to by stupid leaders, leaning back in a nice chair while others die. Watching this soldiers is a light in the dark among humans.

When that guy died from laughing after seeing a donkey eating figs

Probably when Alan Turing was working on his machines!

first thing in my mind would be the moon landing, but its so well documented, that we are basically observers of it. idk, its hard to pick an event