The Holocaust.
If you could change one thing in the past and you had worldly powers to do so what would it be?
Being Born🎺.
To never have had the fiasco called the Vietnam War ! So I never would have had to go to that hell hole. Quite a few friends and my brother would still be around if that never happened.
I would have never befriended some one I should have NEVER trusted! It had devastating effects!
There are two. I have had two friends who committed suicide. A few days before the first one he asked me what he could do. My answer was I didn't know. I wish I would have told him to hang on. Things do get better with time.
The second one I had this urge to call my friend. I didn't. I pushed it off and told myself I would call on my next day off, which was two days away. That morning I got the phone call that my friend was dead.
While I can not go back and change those moments, I can learn from them, and have. I never put off those urges to call, and I always tell people that life changes. You just have to hang on to get through the rough patches.
Jenna Marbles, a very famous YouTuber, recently made a YouTube video "30 things I learned in 30 years", and one of them was that the decision you made in the past was the best one you could've made at that time. I think she's right.