Riddle of the day:

Having spent a week creating kennings and riddles with the kids at Wallasey School, I am obviously in that mode now. As I was coming back from the shops today I came up with a new riddle; I'll probably rework it to rhyme at some point, but here it is:

I saw a green field, eight feet below the ground,
on it people of all races,
doomed to fight or to be swallowed whole.