So most everyone knows about the area East of Echo Islands, where there are blocks of "non-fatigue" water, which connect to a long strip of land that marks the "end of the world" in a sense.
I myself had never been there, so I got on my lowbie UD priest and decided to check it out. The first thing i noticed that was interesting was after i had died and was running to my corpse, if you look at the water, you can visibly see these patches of non-fatigue water far out:
So i eventually get to the non-fatigue area, and i come across a hole in the water:
According to the map, there should be a hill or some piece of land here. Not sure where it went, I decided to jump in.
What happens next? I fall. Far. Really Really far. I fell to the utter bottom of the world.
Picture doesn't show much, but the water was "clear" and not blue and the ground flat. So i swim up, and it took a long time. If you attempt this on a char that is not undead, you will die. When i surfaced i was at about 1/4 on the breath meter.
Happy that I did not die, I look to where the last bit of land is, or should be at least:
It appears that the land was removed, same as the land missing from the hole in the water. I would have tried to get to where the land used to be, but I didn't feel like getting stuck or swimming a lot.
So that's my exploration adventure. I do see a somewhat practical use for this, however mean it may be. I saw this being done on a video, linked from MMOWNED I'm sure. I'm not sure exactly where it was done, but this would be a good place too. As a lock, fall down the hole and sit at the bottom with a few friends, and summon people. The summoned try to swim up, but just end up dying. I think it would be fun at least.