In the cold, gray waters of the Gulf of Finland, 30 kilometers west of St. Petersburg, a giant wall juts across the bay. Completed seven years ago, it protects the city from an age-old danger: floods. 

When storms approach from the west, the Baltic Sea is pushed eastwards into the shallow Neva Bay where the city lies. There, it collides with the fourth largest river in Europe by discharge, the Neva, causing water to spill over the riverbanks and overflow the hundreds of canals that crisscross the city center. 

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“When the floods happen, the wind knocks you off your feet and it’s hard to see anything because of the rain,” says Olga Suvorova, a press secretary at St. Petersburg’s Flood Prevention Facility Complex. 

Over the past three centuries, the “Venice of the North” has suffered more than 300 floods, two-thirds of which saw water levels rise above the “dangerous” mark of 2.1 meters, according to Russia’s Hydrometeorological Center.