Answer:
I run around the city, but I never move.
Soldiers line up spaced with pride. Two long rows lined side by side. One sole unit can decide, if the rows will unite or divide.
I am the heart that does not beat. If cut, I bleed without blood. I can fly, but have no wings. I can float, but have no fins. I can sing, but have no mouth.
What is it which builds things up? Lays mountains low? Dries up lakes, and makes things grow? Cares not a whim about your passing? And is like few other things, because it is everlasting?
Round as an apple, deep as a cup, and all the kings' horses can't fill it up. What is it?
Dark, feathery, and popular in Baltimore and fantasy books.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?