An unusual location once resulting from a generation bug in Minecraft: Bedrock Edition, the Far Lands would appear millions of blocks from the origin of a given Minecraft world.
At the time of the Far Lands’ existence, the massive and unusually-shaped location resulted from a bug in Minecraft: Bedrock Edition’s terrain generation code.
The Far Lands essentially served as the end of a given Bedrock world before the game’s code was refined and it became possible to generate more of a Minecraft world. This applied to dimensions such as the Nether and the End as well, and the Far Lands could also be seen in Java Edition as well (though they operated slightly differently than the Bedrock iteration).