What do you think is the most useful invention?

In my eyes it is the printing press-without it not so many people by far would be able to read, and it also sparked off new inventions and ideas making the technology as advanced as it is today. some people say it's the wheel but it is not as influencial and anyway nobody knows who thought up this idea as it is too caveman so no-one knows who came up with it but it was probably just from common sense.

You probably think that I am a bit geeky writing this but if you don't then pls comment about your choice...

VS