Russian Prime Minister Vladimir Putin took part in the opening ceremony of a dam in St. Petersburg.
He called the construction of the dam a historic event. The prime minister inspected the room where controllers will be watching the work of the system.
Over 30 purification installations have been placed in the water around the dam. The gulf has already been cleared of seaweeds and this summer the residents of St. Petersburg prefer to swim in sea water rather than in pools.
The dam can protect the city from water rising to 5m. According to statistics, water rises up to 100 times a year in St Petersburg.