Worlds most modern ancient advancement

The only thing that bothers me is the purpose of them.  Sure, elctroplating.  But surely there must be some other purpose too?

But why must there be some other purpose?
For a while Europeans realised you could stick two pieces of metal in a citrus friut, and get some off prickle feeling from it, it was only in the 1800s that some Italian realised that this was effectivly a battery and that that pricling sensation was current, and even then it took a while before people figured out what to actualy use it for.
And alternative uses are not always obvious. Clockwork mecahnisms had been around in Europe for the best part of half a millenia, possibly longer, and radios for about a century, electric dynamos even longer, but it was only a decade ago that someone thought to combine those three elements and make a clockwork radio, despite how obvious and usefull it may seem, no-one though to do it, (or there again, maybe they did and it was dismissed, over looked, etc.)

Its highly likely that someone realised that it could be used in electroplating by playing around, without understanding the inner dynamics of what is going on.
Its easy to say, "ah, thats a battery, they could have done so much more with it", but if they are not aware of what a 'battery' (as we know it to day) is, or what exactly is going on, then that whole window of opportinity that we see is invisible to them.

And perhaps the invention didn't spread because it didn't really have that much use back then?

Is the most likly scenario.
Take the ancient Greeks and their 'steam engine', technicly it harnessed the power of steam, but it was basicly little more than a nifty party trick, so it didn't get anywhere and was eventualy forgotten somewhat, untill modern steam engines came along and people starting saying "hey, those old Greeks did that too".
There are numerous such examples, inventions are only renembered if there is a profitable use for them, otherwise they are forgotten by the mainstream, and become curiosities.


Edited by Cywr

Others have already mentioned the advancements that are most obvious to me, the Baghdad battery and Hero's steam engine.  However, I can add these:

The world's oldest flush toilet, found in the queen's chambers in the Minoan palace at Knossos.  That's something that would be re-invented in the 19th century.

The cup that looked like glass, but wouldn't break when dropped.  Petronius mentioned this in one of his stories about the Roman emperor Tiberius, who then killed the inventor because he saw this as a threat to the stability of Rome.  It may not be true, but if it is, we could have an early form of plastic described here.

The iron Ashoka Pillar, which has been standing out in the Indian climate for at least 16 centuries without rusting.  I believe only last year was a way found to cast a pillar like that.

The skull of Rhodesian man, the first Neanderthal found in Africa, has a bullet hole in it!  Did he actually live in the 18th or 19th century, and get shot by a European, or did somebody have guns, thousands or tens of thousands of years ago?