What Am I Riddles

Question: I am a cave full of bones,
and the house of a worm.

What am I?

Question: What has 4 fingers and a thumb, but is not living?

Question: I cannot be seen, cannot be felt,
Cannot be heard, cannot be smelt.
I lie behind stars and under hills,
And empty holes I fill.
I come first and follow after,
End life, kill laughter.

What am I?

Question: Hold me by the neck and I won't mind,
if I get wrong I just need a good wind.
If you want me you better pick wisely,
just use your ears and I'll follow you blindly.

What am I?

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?