Answer:
You may enter, but you may not come in. I have space, but no room, I have keys, but open no lock. What am I?
Use me to reward good behavior.
I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?
Squeeze me and I cry tears as red as my flesh but my heart is made of stone.
I march before armies a thousand salute me. My fall can bring victory but no one would shoot me. The wind is my lover one-legged am I. Name me and see me at home in the sky.
I run through hills. I veer around mountains. I leap over rivers. And crawl through the forests. Step out your door to find me.