Answer:
Without this, H2O would just be 2O
War fought with pieces on a board.
Mountains will crumble and temples will fall, and no man can survive its endless call. What is it?
A standard dimension for sandwiches and rulers
Though I should be unique, you've made most of us the same. I would be stronger, if my characters were stranger.
Two little holes in the side of a hill. Just as you come to the cherry-red mill.