Venice is facing its worst flooding in 50 years... as high tides send more water through the city.

Mayor Luigi Brugnaro said, "Venice is on its knees."

The flooding has resulted in more than $1 billion in damage to historic monuments, businesses and homes.

But nothing can stop the holiday spirit in Venice. 

Santa Claus was there wearing his boots with thigh-high galoshes in St. Mark's Square where witnesses reported seeing waves. 

Tourists and local residents were also out in colorful rain boots.