After about a week (about 6 hrs total) with Aquanaut's Holiday, I just
wanted to share the things I've seen, and as others to post what they've
seen.

OBJECTS:
*The Great Wall of China (very cool looking, but you can't even swim
through it or over it...if you try, it says you've collided with it - an
invisible barrier...)
*A shipwreck (also cool, but it would have been cooler if it were bigger
and you could swim among it's spires and inside the hull.)
*A face (whatever...)
*A transparent sphere with another sphere inside of it.  It was just
floating there...I don't really know what it is.
*An acqueduct (lots of fun to swim between the pillars)
*Three rocks in a triangular shape

STUFF:
*A very cool hole in the ground that just kind of goes down and down and
down.  It does end eventually, so it's like a cone, but it's still kind of
neat.
*I found the fossilized remains of a fish in a green plant.
*A long trench

FISH:
*Some really bizzare looking ones, that I think have to be prehistoric. 
They just don't look like they're from this planet!  I've got to go to the
library and see if I can get a book that'll tell me what the majority of
these things are.
*I like making them spin around and show off in front of me, especially
the manta rays.  They keep looking at you like they're waiting for you to
do something else.  They just sit there and so I feel bad when I bump into
them as I try to leave.
*I've seen big black whales, a brown one, and a white one, but I can't get
any of them to do anything.
*I saw what looked like a shark, but it was a very light pink, almost
white.  What was that?
*I like swimming in with a school of fish.  It's fun!  Try it!

REEF:
*I only just started this the other day.  I was having too much fun
swimming around that I forgot about it.  I've just been putting blocks
down and mixing up colors in checkerboard and stripe patterns and I've
filled my "fish-meter" halfway.

I've really been enjoying this game.  It's a lot of fun to just swim
around and see what you can see.  Sometimes I become intent on finding
some kind of underwater wreck or something, and then it's not as relaxing
because I get frustrated.  It's more fun if you just swim around aimlessly
and just happen upon things.  I also like playing with the fish.  My
friend sees me playing it and doesn't understand.  He wants to kill them. 
Oh well...can't expect everyone to get it.

Keep swimming!
- Chris