What Am I Riddles

Question: What always eats but is always hungry?

Question: I'm round at the ends and high in the middle.What am I?

Question: My food and drink were left behind
by ancients from another time.
I grind my feet upon the earth
with strength come from a metal hearth.
My mind is trapped when I run free
when still, it wanders far from me.

What am I?

Question: What goes up, lets out a load, then goes back down?

Question: I have numbers on my face but can't find 13 any place. What am i?