As far as coins are concerned, there are different ages over time when design had reached crescendos in beauty and design. What are the great periods in world coinage for different empires and nations for their peak coinage designs?
There's more answers for that than there are coins themselves, and there's a boatload of coins ! Of course the reason there are so many answers is because beauty lies in the eye of the beholder. What I think is absolutely gorgeous, you or someone else may think is ugly. As for time periods and for my taste, from the 1300's through the early 1900's would be it. Countries vary from Italy, Spain, Germany, France, the Netherlands, Great Britain, Austria, Hungary, the US, you name it, they are all pretty much in there.
Some people like wartime coins (e.g. wartime nickels) or coins struck in years of personal importance, like a collector's birth year.
