Ramanujan
An obscure Indian clerk, self-taught, raised in poverty in Madras, sends a letter to Cambridge with his work, ends up a Royal Fellow, considered one of the greatest mathematical minds of all time.
https://www.youtube.com/watch?v=PqP2c5xNaTU
https://www.youtube.com/watch?v=y_0NuOBNobk
Slightly fictionalized biopic :
https://www.youtube.com/watch?v=8WwLPep9xNg