The Chinese communist famine of 1959-1961 was unknown to the outside world, the communist successfully covered up the death of tens of millions of their own people until 1979.
In 1979 a French statistician noticed the evidence of the famine in a table listing Chinese population numbers and that was how the world outside of China first found out about the deaths of tens of millions of Chinese citizens during the faming 20 years after the fact.
All of the world's journalists and diplomats had no idea for two decades until a math guy sussed out reality for them, it was a big moment in the history of mathematics.
cool story or cringe?