Answer:
I saw the dead bring forth the living. I saw the living bring forth the dead. What did I see?
A caribbean shape that makes ships disappear.
As I went over London Bridge I met my sister Jenny; I broke her neck and drank her blood and left her standing empty.
I stay where I am when I go off. What am I?
I am enjoyed by some, despised by others. Some take me for granted, some treasure me like a gift. I last forever, unless you break me first. What am I?
What is lighter than what it is made of?