Trungsund (Leningrad region) The Russian fortress Trungsund (from the Swedish strait) was built after the Crimean War, in the 60s of the 18th century. It was established to control the strategic route leading to Loiburg. However, due to the rapid development of artillery, the fortifications lost their military significance already in the 80s of the 19th century. Now these are picturesque ruins among granite rocks. Nearby is the tiny town of Vissotsk with a population of about a thousand people. The taxi driver who took me to the fortifications used to work at the castle and told me that soon the Vyborg Museum Reserve will hold an open competition for possible ideas for the development of Trungsund.