A large castle constructed using primarily Ender Stone. For a bit of fun, try knocking this one down - I built it as good as TNT-proof. Featuring 8 cannons, many fire arrow launchers and plenty of chests, the castle is also empty in the middle, allowing for you to fill it with an arena, mob spawners or massive halls as you desire. Note that this castle has no gate: it was made for a castle battle, where a gate would only have weakened it. The doors on the outside hide the fire arrow launchers; they open before launch and close again after each volley. Have fun, and let me know if you manage to take it down without using instantmine or mods.

Additional Notes

Try not to mine into the walls, it has a habit of lagging when all the water rushes out.