St Mark's Square in Venice was underwater late on Saturday night after a rare "acqua alta" or high water event.
As a city of canals, Venice has come to expect some flooding between autumn and spring each year during ‘acqua alta’ aka the high tides. But this summer flooding is very out of character for the city.
Due to climate change and rising sea levels St Mark’s square has gone from flooding four times a year in 1900 to over 60 times a year now.
Tourists didn’t seem too put off however, with many choosing to take off their shoes and wade through the water.
Why does St Mark’s Square flood?
Venice is situated in a lagoon at the northern part of the Adriatic Sea. Due to a combination of factors including the alignment of the Sun and Moon, sea levels are known to rise significantly during certain times of the year.
The lowest part of Venice is right in front of St Mark’s cathedral on the square, which is just 64cm above sea level, and so is always the first to flood.
The city has invested in a flood defence system, MOSE (Modulo Sperimentale Elettromeccanico which translates to Experimental Electromechanical Module) which after much delay was used for the first time in Autumn 2020.
The system works using a series of movable gates which can isolate Venice from the Adriatic sea when the high tides occur. However MOSE is designed to kick in when the tides rise above 110cm high and so on this occasion the flood defence system didn’t protect the city.
Watch the video above to see St Mark’s Square under water.