Balkan, Slavic,... to the rest of the world tag

Suomenlinna is sea fortress built on six islands (Kustaanmiekka, Susisaari, Iso-Mustasaari, Pikku-Mustasaari, Länsi-Mustasaari and Långören) and part of Helsinki, the capital of Finland.

Suomenlinna is a UNESCO World Heritage site and very popular with tourists and locals. From
Mainio.