Am I the only one who thought the metal structure with the hatch/numbers is a boat? Looks really similar to either a submarine, or some type of armored amphibious vehicle.

I have seen other people mention that as well, but I believe the consensus is that it's more of a hatch or underground bunker of some type.

Submarines, at least the military type, do not usually have windows.

You have a screen shot of that "window" Adam? I never saw one, i could be wrong, but it looked like a hatch... and it's very possible it's a submarine.... altho how it got in the middle of the island.. i dunno haha.

That's how the island got there! It's vegetation that grew on top of the wrecked submarine. :lol2:

Could be anything contructed early to middle 20th century that has to do with Sea going vessels or Military in origin. Still, could have been constructed on sight or marrooned there like everything else?

The window seems to be extra thick... like that used on a sub or some other device that is resistant to pressure (water, or how about the vacuum of space). The hatch is also held on by very large rivits, this structure seems to be made to be very strong and the edge looks welded. There is a handle on the outside. The rest of the object seems to be at least partly tubular (like a silo with the hatch on top, only from what we have seen so far).
I wonder if the object is like a sub to protect people on the inside, or a cage/tank to hold something?...
Just organizing my thoughts.

I'm sure I'm wrong but thought I'd share anyhow.* When we first saw the hatch my thought was of a diving bell. Since Danielle's was a scientific expedition thought it possible they could have one on board.* Just what were those scientists on route to study/experiment with?* And what kind of scientists were they?*
And how come almost every time I post a thought I think of more questions??? :-\

I didn't see a window, either...but ayway, I'm still sticking with my thoughts before. I still think it's a hatch.