AlphaGo Defeats Lee Sedol

From March 9–15, 2016, DeepMind's AlphaGo defeated world champion Go player Lee Sedol four games to one in Seoul, South Korea. Go had been considered the game most resistant to AI mastery due to its combinatorial complexity — estimated to have more possible positions than atoms in the observable universe. The victory, broadcast globally and watched by over 200 million people in China alone, demonstrated that deep reinforcement learning could achieve superhuman performance in domains previously thought uniquely human. AlphaGo's unconventional "Move 37" in Game 2 was widely described as a move no human would have considered.