A tag used to specify real-world puzzles which usually do not have a solution at the time of posting. This can include widely-known puzzles that have remained unsolved for some time.
This tag is most generally used when posting a real-world puzzle/mystery, and as such, the ability of the poster to provide additional details may be limited. It can represent a widely-known unsolved mystery, for which there is often a low expectation of the community actually finding an answer.
Current unsolved real-world puzzle
Some puzzle are made by some brilliant minds and are worth sharing. There often is no known solution and sometimes no proof that is possible.
Should these be merged? If not, how are they different? When would you tag a question with one, but not the other?