Answer:
Upon me you can tread, though softly under cover. And I will take you places, that you have yet to discover. I'm high, and I'm low, though flat in the middle. And though a joy to the children, adults think of me little.
They can be harbored, but few hold water. You can nurse them, but only by holding them against someone else. You can carry them, but not with your arms. You can bury them, but not in the earth.
Who has married many women but never has been married who is he
Two horses, swiftest traveling, harnessed in a pair, and grazing ever in places. Distant from them.
What has two spines and a lot of ribs, and carries much but never moves?
What language does a billboard speak?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?