in the domain of dos pilas was punto de chimino, located on a peninsula jutting into lake petex patutun. here there's a break in it where it drops down into this little bay. keach: while surveying the region, demarest discovered that what at first looked like a natural ravine was in fact a manmade channel, a kind of moat, like those that encircled medieval castles. you can see where the moat was. originally, the water would have run all the way across to the other side where you can see the sky. keach: the moat was apparently designed to cut off the peninsula from the mainland, making it a highly defensible island. on the city side of the moat, demarest found the earth built up into a long, steep incline. demarest: see how steep this is right now, how difficult to come up. it was probably originally almost vertical. and it would have been much more difficult if you had some maya up at the top hurling spears and rocks down on you. keach: the archaeologists think that for further protection there would have been a tall wooden fence on top of the embankment. demarest: this whole thing seem