I’ve been wasting hours on Terraria (which is an awesome game btw) and here’s the result, my own castle 😀 (click on the image to get a full-size version)
This was all mined and constructed in-game using my trusy Molten Pick-axe, Molten Ham-Axe, Jet-Boots and Ivy Whip. My two boys helped me a bit too, especially on the mining (those blue dungeon bricks are damn tedious to mine!) 😉
If you want to download the Terraria world file, here it is (zipped up for efficiency, make sure you unzip it before using it!):
N.B. Please be careful when copying this world file into your Terraria Worlds folder. Because it’s named WORLD1.WLD it will likely overwrite your own first world file unless you rename it!