Estonia, it seems.
There is a lot of hype and there is also a little bit of substantial movement. So every once in a while, Business Insider will come up with an article that says “this country is going to have cryptocurrencies now” and then you discover that it’s just a pilot project, and they are just trying to see what they can do. I am not really sure how far along Estonia is, they already had their digital citizenship programmes, so it seems that they already have the infrastructure needed to build the system much more conveniently than other countries, but I’m not sure how far along they are on that front.