I ask because while I was playing The Knights of the Nine's quest to find the Shrine of the Crusader, I had a thought hit me; Why is Vanua under the lake? Did the entire facade just sink underground? It doesn't make much sense to me since the interior doesn't look 'ruined' as it caved and only flooded., so was the IC's hill possibly once solid hill or a small lake before the current (at the time of Oblivion) time? I ask here because I'm not very versed on the finest points and thought maybe someone might know.