Here is the Hardest Riddle in the World, so far...
The Hardest Riddle
Once solved, here's the answer.
The Hardest Riddle, The Answer
Here's another. It's not as tricky but has a good reputation as being hard, and it's fun to do.
Albert Einstein's Allegedly Hardest Riddle
And the answer.
Albert Einstein's Hardest Riddle, The Answer
And if you liked those...
Join me in the next one.