What Am I Riddles

Question: My shallow hills are the faces of kings.
My horizon is always near.
My music sends men to the grave.
My absence sends men to work.

What am I?

Question: What is brown or silver, has a head and tail but no arms or legs?

Question: I have a few points but we're not competing.
And I'll help you win when you're eating.

What am I?

Question: It brings light to a dark dark world,
In a current it travels and through tunnels it's hurled.
Touch it and it'll kill you.

What is it?

Question: I used to fill rooms but now I'm a tower,
I can stay put or I can travel far.

What am I?