Venice, Italy — Residents in the picturesque Italian city of Venice are used to the canals inching higher every year around this time. But this year has brought the worst flooding in half a century, and the second-worst since record-keeping began.

Venice sits on a tidal lagoon, just above sea level, so the city's squares and streets often get wet at high tide. This week, though, the water peaked more than six feet above the usual level, and at least one death has been blamed on the flooding already.

CBS News correspondent Holly Williams reports that 85% of Venice has been flooded by this year's "acqua alta," or "high water."

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When your city is built on a lagoon, water is a fact of life. But Venetians have told Williams that what they're seeing this year is not normal. The mayor has called it "apocalyptic."

Moon Najmul, standing in near-chest-high water in her souvenir shop, told Williams that all of her family's five stores were flooded.

The luxurious furnishings of the Gritti Palace, a hotel for the wealthy and famous, were left sodden and destroyed.

Flooded St. Mark's Square in Venice, Italy, in front of St. Mark's Basilica, on November 14, 2019. GETTY

In a city that earns a living from its gorgeous views and the tens of millions of tourists who come to see them every year, the inundation is a disaster.

The iconic St. Mark's Square has been a tourist attraction for more than 300 years. This week it was submerged in water so deep that one man was seen using the famous piazza as a swimming pool.

It has been a perfect storm of high winds, a flood, and a city that sits only four or five feet above sea level. But experts and some government officials say what's making things worse in Venice is climate change and rising sea levels.

"This is the result of climate change," Venice Mayor Luigi Brugnaro said bluntly on Twitter.

St. Mark's Basilica, a structure that dates back around 1,000 years, has been flooded just six times in its history — twice in the last two years.

The flooding has caused hundreds of millions of dollars in damage to a jewel of a city so precious that it has long been designated an official World Heritage Site.

Venice has been building new flood barriers since 2003. They are still not finished, and some experts fear even if they were, they won't be sufficient to solve the problem as the sea outside the Venetian Lagoon gets higher.