Answer:
Weight in my belly, Trees on my back, I travel fast in my place, but feet is a feature I lack
I build up castles. I tear down mountains. I make some men blind. I help others to see.
The higher I climb, the hotter I engage. I cannot escape from my crystal cage.
They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own.
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.