I am a currency of a country that is not only known for its rich history and beautiful landscapes, but also for being the birthplace of a famous scientist. This country is a land of contrasts, with bustling urban centers and serene natural wonders, and its currency reflects the resilience and diversity of its people. What currency am I?

1. My country is located in the Balkan Peninsula.
2. I am not part of the Eurozone.
3. My national language is closely related to Serbian and Croatian.
4. My symbol is 'ден'.