The neatest thing I've seen on the interwebz in a while: Detailed sonar pics of shipwrecks in Scapa Flow.
One of the more interesting things there is image of the wreck site of SMS Bayern. Note her gunhouses all lined up in a neat row on the sea bed. I remember being surprised the first time I read of a battleship's turrets falling out as she capsized, then realizing that you really don't need anything other than gravity to keep a 2000 ton turret stuck to the ship as long as it remains right side up. (And if it's no longer right side up, who cares if the turrets stay attached, really?)