Garry Kasparov, then considered the greatest chess player the world had ever seen, was defeated by Deep Blue, a kind of rudimentary artificial intelligence. It was the first time a computer had beaten a human as part of an official regulation match recognized by the world chess establishment.
The man-versus-machine contest followed years of experimentation, with researchers trying to best the world's chess heavyweights. Sometimes, they succeeded; several grandmasters had already been beaten by the bots. The version of Deep Blue that premiered in 1996 was the most advanced digital "mind" out there at the time. Kasparov would ultimately triumph over the bot, winning the six-game match with two ties and three wins.
You can read more about Deep Blue on the IBM website.
