Last Month’s Riddle

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Answer: 
On top of the person’s head.

Thank you to all of you who submitted correct answers, but, unfortunately, we only picked one winner. We hope you try this month’s head scratcher!