-Murder Holes : First, dig a 2 block deep hole in the ground. Dig another hole 3 blocks deep, 1 block away from the first hole. Dig out the block that separates the bottom of the 2-deep hole with the middle of the 3-deep. If done correctly, this should allow all mobs (except for spiders) to fall into the 2 block hole. Then, you simply go into the 3 block hole and attack their feet. Murder Holes often function best alongside a perimeter wall of some sort, with the 2 deep outside and the 3 deep inside. An extra addition to this is to make a large amount of murder holes, and form a tunnel system of sorts, so you can watch multiple holes at once.

-Snowgolem Defenders : Since snowgolems shoot Mobs back, consider adding holes in the sides of your walls with little rooms attached to each hole. Then build Snow Golems behind each of the holes. You should be placing the pumpkin head 1 above the hole, because when the snow golem is formed, it is only 2 blocks high.

-Skylight : Although this may not sound like much of a defence, building a small skylight above your entrance/exit will allow you to easily see any mobs (Especially spiders) waiting to pounce on you from above.

-Anti Hostile Mob Passageway : You can use the fact that snowballs push hostile mobs, by building a 1-wide bridge over lava and putting snow golems on the side . The player and passive mobs can pass through safely, while hostile mobs will be pushed to the lava by the snowgolems' snowballs.

-Moat : The simplest of these is a "dry moat" or trench, a couple layers deep so that Skeletons and Zombies can't get across. This can provide you with a reasonably safe area that is outside. This can be filled with water to push the enemies to a mob grinder. Tower shelters would do well to have a three-block deep water moat to break the player's fall so they can safely fall to the bottom.

-Lava Moat : If a dry moat won't work for you, try adding lava to the Moat. Just remember that dont make the lava moat to near to some flammable objects.

-Wall : A simple defence is to Build a large wall, light the area inside and you can live "hostile free". you can use dirt but to make it look nice, try to use obsidian

-Self-Rebuilding Wall : A more effective but complicated wall. It's possible to apply the idea of a cobblestone generator and use pistons to make it automatically rebuild damaged walls. Generally more effort than it's worth, but very neat-looking.

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