Minecraft wiki entry for Shelters, associated text: The jail is where rule-breakers or criminals go if the punishment agreed on is not an execution/banishment/ban. Build a secure room with traps outside cells to prevent criminals from escaping, via bugs and digging, like lava flowing from the top of the jail. It is very hard to make a secure jail without using Bedrock or obsidian. An alternative is to have the walls of the room constantly being moved by pistons, so the player has no time to break through them. However, this will create a lot of lag. You can make a regenerating wall using water and lava as well. Be warned, however, that if the spawn is outside the jail, the criminal can use the /kill command to escape or blow themselves up with TNT. Also, remember to never send an admin to jail without reverting their admin status first or they can just switch themselves to creative mode and mine the thing you made the jail out of.