Another treasure trove would be the bottom of the Black Sea, due to the sterile and lifeless nature of the lower layers of the water. Since even the bacteria which cause decay are missing there, wrecks have been found almost perfectly preserved.
Thanks thsr. Robert Ballard went looking for any traces of human habitation and wound up finding a wreck instead. Also, there’s this:
http://www.freerepublic.com/focus/chat/2141182/posts