Answer:
Once you know it exists, it no longer exists. What is it?
A defendant will go free if a reasonable amount of this exists.
It is a popular afterlife destination where you want to send people when you're mad at them.
Power enough to smash ships and crush roofs. Yet it still must fear the sun.
Big as a saucepan, deep as a cup, Even a river can't fill it up. What is it
Two little holes in the side of a hill. Just as you come to the cherry-red mill.