Answer:
A precious stone, as clear as diamond. Seek it out while the sun's near the horizon. Though you can walk on water with its power, try to keep it, and it'll vanish in an hour.
What has roots that nobody sees, and is taller than trees. Up, up it goes, and yet it never grows.
A house full, a yard full, a chimney full, no one can get a spoonful.
I am a box that holds keys without locks, yet they can unlock your soul.
In this place, people lie, people cry, and people ask why. In this place, people sleep, people weep, and people's solitude, they keep. What is it?
What has wheels and flies but is not an aircraft?