Minecraft - Versioning your saves
Check the new version instead.
This is a tutorial show how to version your saves using Git.
Q: Why would anyone go through this process?
A: Because if you do, you can undo an otherwise un-undoable action, such as swimming in a pit of lava and accidentally dropping your Notch armpit forged special edition diamond pickaxe and your 35 stacks of cobblestone.