This is the rogue warriors' medieval fortress. My friend helped me build it. As you can see in the pictures, the back opens up and there is a trap door into the dungeon. It is modified slightly from the most recent pictures, so I will have some more up eventually.
It's very good, especially the way the walls fold out. Nice job on the bridge and river, those two baseplates really flow (ha ha) together. Also, there are Fright Knights, which makes the castle doubly awesome. Great work!