October 7th, 2017

Croatia does not use the Euro, although it is obliged to adopt the currency once certain economic conditions are met. Instead, it uses the Kuna, with colourful notes featuring historical figures and events. On the 100 Kuna note is a peculiar script next to Croatian poet and linguist Ivan Mažuranić. This is the Glagolitic Script and the excerpt is taken from the Baška Tablet. The script was developed in the 9$^{th}$ century by a Byzantine monk, making it the oldest known Slavic script. The tablet dates to around 1,100 and contains a liturgical inscription bearing the first known reference to the Croatian name of Croatia (hrъvatъskъï, or Hrvatski). As for the script, it slowly declined beginning in the 17$^{th}$ century, and Croatia was one of the final regions where it was used (primarily for liturgy) before disappearing entirely in the 20$^{th}$ century.

Bonus:

There are currently 9 EU countries that do not use the Euro: Bulgaria, Croatia, Czech Republic, Denmark, Hungary, Poland, Romania, Sweden, and the United Kingdom. Of these, all are contractually obliged to join as part of their EU membership except the UK (which will leave the EU in 2019) and Denmark (which opted out of the membership provision). There are also two non-EU countries using the Euro: Montenegro and (if you count it) Kosovo.

-E