Answer:
It is sometimes known to have silver linings.
Crooked as a rainbow, and slick as a plate, Ten thousand horses can't pull it straight.
We travel much, yet prisoners are, and close confined to boot. Yet with any horse, we will keep the pace, and will always go on foot.
I don't have eyes, but once I did see. Once I had thoughts, but now I'm white and empty.
What has six faces and twenty-one eyes?
You can always find me in the past. I am created in the present, but the future can not change me. What am I?