Minecraft wiki entry for Multiplayer_PvP_bases, associated text: If you really don't want your base to be defeated, you can choose to have no entrance, block up all the entrances and reinforce the weaker walls with 3 layers of obsidian, leave the elder guardians there, and enter only using /home or nether portals. This method is possibly the most effective out of all the bases, as it takes multiple days for even an experienced group of players to remove enough water for TNT to be an issue (if they don't remove enough water, the water will flood any area they attempt to blow up, undoing most of their work), and mining 3 layers of obsidian under the effects of mining fatigue III will take over thirty hours using a Diamond Pickaxe (257 hours using bare fists). This is just to destroy enough obsidian to fit a player through. Even with Efficiency V and Aqua Affinity, mining through will still take 1.5 hours. Nobody will bother to do this, especially when they're drowning underwater with a crowd of guardians firing lasers at them. Also, slab the entire area around your base, so that players cannot take breathing spaces by placing doors everywhere, and slabs don't clear enough water for players to breathe.