Demis Hassabis
They created AlphaGo, a program which defeated world champion Lee Sedol at the complex game of Go. Go had been considered a holy grail of AI, for its high number of possible board positions and resistance to existing programming techniques. However, AlphaGo beat European champion Fan Hui 5-0 in October 2015 before winning 4-1 against former world champion Lee Sedol in March 2016.