Hero of Alexandria, in Roman Egypt, described a steam engine 2000 years ago. He is credited with inventing the first steam engine, although it is very likely that he was just describing something already in existence as previously described by another Roman, Vitellius, a hundred or so years earlier.
Today I saw a working example of a Hero type engine, and it was much more impressive than I expected. One of our club members has built 2 Hero engines, and the following video shows one of them working.
I think that I will have to make one to show the grandchildren.
Click on the arrow to see another grossly amateurish video.
Incidentally, Emperor Nero, who hated his mother, put her in a ship which, as planned, fell apart when afloat with mummy dearest on board. Unfortunately for Nero she could swim. What is really interesting is that the ship is described as having some sort of mechanical propulsion system. Maybe steam??