Difficult

I can move even when you are still. I can be one or many.

Above all things have I been placed Thus have I, a man disgraced. I describe sunlight or lock But after all, I'm just a rock

Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.

What does a WW1 Trench, A Submarine and a Popular Phone App all have in common?

Riddles and Answers