Google's DeepMind AI beats Europe's Go champion
Ever since the modern computer was invented there's been one nagging question - who's cleverer?
You might remember, IBM's Deep Blue beat the reigning chess champion Gary Kasparov way back in 1996.
In the latest round of the man versus machine contest a computer has beaten a professional player at Go.
It's a Chinese game that is even more complex than chess and is played by more than 40 million people around the world.
The BBC's technology correspondent Rory Cellan-Jones explains the achievement's significance.