IN PHOTOS | Glass shields Venice's 900-year-old St. Mark’s Basilica from flooding

A set of glass barriers installed around the 900-year-old St. Mark’s Basilica in Venice has kept its marble columns and valuable mosaics safe from seawater-induced erosion. Flooding in November 2019 was devastating because the water could not recede quickly following repeated deluges, leaving parts of the basilica submerged for up to 24 hours.

A set of glass barriers installed around the 900-year-old St. Mark’s Basilica in Venice has kept its marble columns and valuable mosaics safe from seawater-induced erosion. Flooding in November 2019 was devastating because the water could not recede quick 

Even after it evaporates, water leaves behind salt crystals that corrode the marble bases of the columns and the floor mosaics, said Mario Piana, the architect and restoration expert in charge of St. Mark’s. (Photo | AP)

The new barriers are made of glass mounted on a base of armored concrete that is buried below the pavement of the famous St Mark's square to resist the force of surging water. Procurator of St. Mark's Basilica Mario Piana said the system could keep out up to 1.10 meters (3 feet, 6 inches) of water in the square, equivalent to a tide of 1.90 meters (6.2 feet) above sea level. (Photo | AP)

Built on log piles among canals, the palatial city of Venice has grappled with flooding since its foundation 1,600 years ago. But like other coastal areas, rising sea levels and more extreme weather that scientists associate with climate change have meant more frequent high tides. (Photo | AP)

A couple stops on the fragile marble mosaics on the floor of St. Mark's Basilica for centuries endangered by seawaters in Venice, northern Italy. (Photo | AP)

While the basilica was built on what was one of Venice’s highest points at the time, it now sits on one of the city's lowest due to subsidence and rising sea levels. Signs of erosion are visible inside St. Mark's Basilica in this picture. (Photo | AP)

St. Mark’s gets more flooding than most places and remains vulnerable despite the activation of the Moses underwater barriers around the lagoon city in 2020 to protect Venice from floods over 1.3 meters. (Photo | AP)

Piana said that the glass and concrete barriers were part of a larger engineering project to set up a series of channels below the surface of the church and its namesake square to carry off water from the lagoon and keep it from flooding the square. (Photo | AP)

Floodwaters getting into the basilica have frequently been happening also out of season, too, making it all the more vulnerable and pushing officials to devise the new glass barriers as a defense.

Tourists and residents walk on catwalks during a sea tide of around 97 centimeters (38.18 inches) to cross a flooded St. Mark's Square in Venice, northern Italy, on December 10, 2022,