As soon as you have the Bottom area dive in and go to the farthest dome
on the left side and go in.  Run along the board walk like piece of
stone and do the long jump just a bit to the left of the rock you see in
the waterfall.  You will land on a platform inside the waterfall with 2
lives on it. Pick them both up and jump off the cliff.  You will lose
the first, but not the second.  You can do this over and over again