Trong Sung

Trongsund Fortress is situated in the north of Big Vyotsky Island near the city of Vyotsk. It was built from 1864 to 1867 and played an important role in the Winter War, becoming the site of fierce battles for the Viaporka Bay. Today, the fortress' grounds are overgrown with forest but parts of the structures remain: earthworks lined with granite blocks, gabions, curtain walls and interior rooms, many of which are in ruins. The name of the fortress derives from Swedish meaning "narrow strait", highlighting its strategic significance controlling access to Viapori (the old name for the city of Vyborg).