How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?
Sharpen your observation skills as you compare two seemingly identical images. Grab a magnifying glass, involve a buddy, and unleash your inner detective. Check the solution to see if you're a difference-detecting maestro!
In 2007, a puzzle was released and $2 million prizes were offered for the first complete solution. The competition ended at noon on 31 December 2010, with no solution being found. Wiki