There’s a play so powerful that an old superstition says its name should never be uttered in a theater. A play that begins with witchcraft and ends with a bloody, severed head. A play filled with riddles, prophecies, nightmare visions, and lots of brutal murder. But is it really all that good? | TED-Ed

Today, artificial intelligence helps doctors diagnose patients, pilots fly commercial aircraft, and city planners predict traffic. And these A.I.s are often self-taught. So how exactly does a machine learn? | TED-Ed