It doesn't have to be an achievement for humanity - it can just be a personal achievement.
Thousands upon thousands of people have done the Three Peaks (a famous walking route in the UK), but I'd still like to do it, and would feel a sense of satisfaction at succeeding.
"Only" about 6000 people have succeeded in climbing Everest as of mid-2022. Interestingly one third of all successful attempts ever have been since 2016, and nearly half of all summits are people doing it not for the first time.
