The argument could easily be made that the 20th century saw the end of many great things. Great, not in terms of their joyous elements, but in terms of their importance. Fascism. Steam power. Communism. The defining qualities of the 1800s. At the same time many of the incipient 19th century technologies ballooned in unforeseeable ways.
If you were to ask students in schools today what was the best invention of the 20th century many would probably say cell phones. But I suspect 'the internet' would be the next most popular.
Maybe video games.
Video games aside, however, cell phones and the Internet are the latest telecommunications developments. Of the two one is more important for teens, while the other is more important for the world.
Tim Berners-Lee is a nicely fitting last installment, since the Internet is the most recent of all of these developments. In 1978 James Burke said the eight most important things of the 20th century were: the modern production line, Atomic weapons, plastic, rockets, television, the jet engine, computers, and telecommunications. The last two he is most speculative about, but certain that they will be game-changers for the next century. Their combination, however, was not yet thought of.
Berners-Lee, in 1990, sent information over the internet. Shortly thereafter he put up the first web page, teaching others how to do the same. While the walls of the iron curtain were coming down, the World Wide Web was being set up. The idea was simple enough. The consequences were devastating.
How much information is on the internet now? As of 2009, about 500 exabytes. That's 500 quintillion bytes. Or 1 million terrabytes. But that was 2009. Now we've more than a zetabyte: 1,000,000,000,000,000,000,000 bytes of information. Times that by three and you have the amount of information Americans consumed last year.
The internet was born of a good idea, a combination of existing notions and technologies. It will undoubtedly, excluding perhaps the atomic bomb, be the driving technology of the first part of the 21st century. It has fundamentally changed information, communication, our neural processing, and much more. But we are like Burke, gropingly trying to guess where the next great innovation will come from.