Of the 195 countries in the world, only three have a tiny amount of purple on their flags. And the bizarre explanation stretches back to the ancient world and the exorbitant price of a rare sea snail.

Meet the four-year-old “genius” can identify all 50 US states on a map – as well as all the major cities in the UK and name all 195 flags of the world. Arthur Weekley has been interested in ...