Invention for a lifetime.

I recently had a discussion with a friend of mine about the greatest invention of all time. There are all sorts of answers depending on your opinion. We can start with the original invention of fire, and to be fair to fire, at some point the creation of fire was ideally the greatest invention ever, unfortunately now, thanks to lighter's and matches (which is practically a dying invention as well), fire hardly seems something we are grateful for. Secondly, we have the wheel. The wheel seems like a great invention, but quite frankly isn't the invention of the second wheel more pertinent than the solo wheel. As the years progress there have certainly been some wonderful inventions that have helped all of mankind. Distilled alcohol should certainly be a candidate, with out it we would have never known Jesus could have turned water into it, and people would hate their lives more than they already do if not for the consumption of alcohol. But even then, as enjoyable as it may be, I'm not sure that alcohol hails numero uno. Planes, cars, and specifically boats, seem like the reason we have ended up on the western hemisphere, but as much as I'm thankful that Christopher Columbus was arguably the worst explorer to sail the sea's seeing he couldn't read a compass properly, that doesn't seem like the greatest invention to me either.  In all seriousness, agriculture is definitely a close second. But the winner for me has got to be the printing press. Every bit of knowledge that we have possessed has been possible because we could read it from somewhere. All the technology that we have today had to be put on paper somewhere first, and if not for Mr. Johannes Gutenberg creation of the printing press, we would still be back in the dark ages.

Disagree? What are your thoughts?