All time best invention, what do you think it is?

Rob says>>>I think all inventions are based on natural observation plus a lot of trial and error. The wheel, for instance, didn't just appear one day--it was developed and perfected over millenia. Same goes for the development of metals, without which we would not have the hammers, saws, adzes, chisels and countless other tools needed to build the beautiful churches and domestic buildings that are featured in this great website. My contention is that someone at some point in time about 8,000 years ago figured out a way to create copper metal from ore--the rest is history. But you've got a point--perhaps metal smelting is drawn out over too long a development time to be considered an individual invention.

I think you hit the nail on the head there Rob (no pun intended) but it does make you wonder how somebody actually started this procedure, bearing in mind the intense heat required to smelt any metal.