Whats the greatest invention ever?

whats the greatest invention ever? I think the discovery of penicillin because it led it becoming one of the worlds most widely used medicines.

can I say more than one???
okay well I would have to say computer, music, cell phone, mall, animal hospitals and people hospitals

if I had to say only one I guess I would say ummm people hospital because the people who work in the hospitals save millions of lives everyday!!!

Garmen, that is with out a doubt the COOLEST thing I have ever seen, its almost like having an angel sit next to you. I just got one for an early bday present. I was driving from Michigan to Virginia, when I got into D.C. it said Sever traffic ahead, finding alternat route. also lets me know what the speed limit is.

I believe two inventions ever made were the computer and the telephone.
Those I think are the two greatest inventions ever!