We like to think that many of our fantastic dreams of the future — from space colonization to artificial intelligence and human enhancement — are fairly recent conceptions. But nothing could be further from the truth. Futurist visionaries have been speculating about these possibilities for centuries. And now, as we head into an era of accelerating change, some of these longstanding predictions may actually come true. Here are nine futurists of the past 400 years whose predictions were ahead of their times.