Microsoft celebrates 10 years of Minecraft by making one of the earliest functional versions available to play online in the form of classic.minecraft.net.
Ten years of creating, exploring and surviving. Ten years of mobs, mods and magnificent creations. Ten years of being consistently amazed by what you've built with our game. Ten years of you digging straight down despite our warnings. Ten years of being endlessly excited to see what you come up with next.
In effect, it's a simple but functional version of creative mode, and you can't save your creations.