Nether Castle or in the term of Minecraft Nether Fortress are usually a protection of Nether Creatures from players like us, it was added in the 1.0.0 Update as in The Official Minecraft. The creatures that usually spawn occasionally there are Pigmen Zombies and Blazes. Only Mushrooms grow on the surface. Inside the Fortress are Glowstone, Netherrack and Netherbricks. They were added too since the 1.0.0 update. The creatures outside the Fortress were only Ghasts. Here is the pictures of them.
Here is the Closer View of the Fortress
Here is the Closer View of the Fortress
