Easy category if we are talking about the rules. In each riddle you will see the picture and you have to answer what you see.
It is the known person ? Try his name. City ? Which one ? And what about animals. space objects, ..
It is quite popular category. Of course there are also some complicated object which you have not know at the first try. then you have to investigate and start searching. Internet is allowed and google is mighty wizard :)
Intelligence Inside
All improovments of intellect has got the base in free time.