Here is a defense I made for Minecraft Youtubers. It is a defense with double obsidian with water surrounding them. So basically it has 8 obby at the base, then water, covering that a ton of more obby, covering that endstone and water over that. There is never one or two single block of water so its a bit difficult to get rid of the water to mine and all of us know that it is definitely difficult to mine in water. Also I did not include glass in the build because its water, TNT i not gonna blow up.