Since I was able to locate the brilliant blue waters of the Bahamas in Felix Bossert’s #354, it falls to me to give you somewhere to look for.
As a newcomer, I have chosen something quite (very?) easy, but apparently the pace of the game is slow right now, so the Schott Rule is not in effect.
This should be a quick game, so good luck.
EDIT: (2012-09-30) It appears that my judgement was off, so here is a bit of a hint: This is found on the edge of a major structure in the southern hemisphere.
EDIT2: (2012-10-07) The structure is in Africa. It is easily found using your favourite search-engine, should you know what to search for.