I think the moon landings were an amazing achievement. People having the vision of leaving our atmosphere and heading off to a satellite orbiting thousands of miles away. Fair dues to them.
Voyager is up there for me too.
Mapping of the genome.
Dropping implements of war and talking, whenever it happens is a great achievement. We don’t seem to learn how great it is though, as we often forget, stop talking and start fighting again.
Anyone who has freed himself from desire and learned to be happy with little possessions has achieved greatness IMO.
You forgot to mention the cat flap.