Long Riddles and Answers

Question: It cannot be seen, It cannot be felt, It cannot be heard, It cannot be smelled, It lays behind stars and under hills, and empty holes it fills. It comes first and follows after, ends life and kills laughter. What am I?

Question: There was a window cleaner who was cleaning a window on the 25th floor of a skyscraper. He suddenly slips and falls. He has no safety equipment and nothing to soften his fall, but he is not hurt at all. How do you account for that?

Question: We are just like people. We grow, we get old, we die off. We come in many different colors. Black, white, brown. We come in a army, there are thousands of us, yet we have no war. But we will still die off over the years. What am I?

Question: Pretend walls have their own civilization. Each wall is a different country with different culture. One wall has its own animal, one wall has its own nut, and one wall has its own street. What are the three things the walls own?

Question: Everyday I stalk you all day long,
With every move you make, I never make one wrong.
I vanish twice a day with the sun's height and fall,
I will follow you anywhere,
even the bathroom stall.

What am I?