Answer:
A great mysterious place that the bold have been known to journey into.
What I am filled, I can point the way. When I am empty. Nothing moves me. I have two skins. One without and one within.
A little pool with two layers of wall around it. One white and soft and the other dark and hard. Amidst a light brown grassy lawn with an outline of a green grass.
What can you catch but not throw?
You heard me before, yet you hear me again, then I die. Until you call me again.
What never gets any wetter no matter how hard it rains?