The Sir’s Castle was originally a project technically from my first world. One that is strange and lost, and included 14 different castles. These castles were spread across my entire world and were connected by a really complex rail system. The castle was graphed to the landscape of a multiplayer map and is currently the only part of the castle project to survive.
The Lightstone Cathedral existed in the same multiplayer world. I got all the lightstone from the triple click method, a bug in multiplayer that allowed you to duplicate anything rather easily. I also had filled the basement with dynamite for no apparent reason using the same trick. The bug has since been fixed.
Edit-The original singleplayer map was found and more pictures will be up soon.