Pikku Mustasaari (Gospitalniy Island)

Once upon the time it was a small rocky island much smaller than its current size. According to Ehrensvard's plans a closed bastion fortification was erected on it in in 1750-70. the fortification consisted of 4 bastions, 3 curtains and tenail wall from it's south side. The picture shows Pikku Mustasaari island from it's north side.