It prompted Venice mayor Luigi Brugnaro to close St Mark's Square and call for more donations for repairs just three days after the Italian lagoon city suffered its worst flooding in 50 years.
The high tide peaked at five feet above sea level just before noon on Friday, flooding most of the historic World Heritage city's centre.
A senior official in charge of St Mark's basilica has called for the monument to be surrounded with a 2 metre flood wall as the building was threatened with flood waters.
Carlo Alberto Tesserin, the head of the board responsible for the church said: "The weather is changing and there is no time to waste, we must save this place."
Mayor Brugnaro said the damage is estimated at hundreds of millions of euros and blamed climate change for the "dramatic situation".
He also called for the speedy completion of the city's long-delayed Moses flood defence project.
Carabinieri officers from the corps' world-renowned and highly trained squad of art experts were being deployed to map damage to art treasures, a job that is expected to take some time.
Mosaics were covered with corrosive saltwater and marble panels were bugling out as the water expanded the brickwork behind the wall.
"A wall is the way to save all this unless Venice's flood barrier is completed and works," Mr Tesserin said.
Many people were rising to the challenge of saving Venice's many treasures.
University students in Venice rushed to libraries and other institutions filled with books and manuscripts to help shift the material to higher levels.
The Italian Society of Authors and Editors, which said Venice's book stores and libraries were "gravely damaged" by the high water, launched a fundraising campaign.
Pitching for donations from Italy and abroad, the group said it was important to "take the side of those who every day are on the front lines for the defence of Italian culture".
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