Whatever was the first invention or discovery made by man has to be the best invention or discovery ever, because every invention builds on, or is made possible by, the one that came before it. For example, the internet would not have come into being without the computer. Also, the computer would not have been created without the discovery of how to produce electricity. See what I mean?
This is why it is also a most silly pastime and exercise in futility to debate who is the greatest ever in any field, be it sports, entertainment etc. The present always builds on the past. End of story.