Since the Pigs and Portals update, the maximum number of blocks that every player may have in their inventory at any one time is 80,000. (Before the Build Limit+ upgrade, the maximum number of blocks you could have in your world was 50,000, and later 70,000.) Because there is a restriction of 333 blocks from the bedrock, players are unable to construct bridges that would allow them to access the islands of other players (default spawning point).