One day I was looking around  on some social media when I found a cool command block creation. It was one of those one command things. I was looking at a few of them and I thought they were really cool, so I made a world to test one out. At the time I had really poor something (unrelated) and it caused the command block creation to not load properly, so I deleted the world. Now almost a year later I decided to make a test world. I removed the name and went to change the generation style to superflat and all that, and I loaded the world forgetting to write the name. This may seem impossible, but I accidentally stumbled opon a bug in the game. When the world loaded I realised it was the old world that I created for that failed command block creation. I explored a bit to find 5 seconds later part of the world I have actually created, along with some of the old world. This was absolutely amazing to me.