Mensa defines itself as the "high IQ" society. But they like to be called "the genius club," which is nonsense. The truth is, you only need to be in the top 1% of people to join. Top 1% corresponds to an IQ of approximately 130. The "genius" IQ starts at 150. Well known people in that group include Sir Isaac Newton (estimated to be 150) and Albert Einstein (estimated to be 180).