https://phys.org/news/2018-10-tourists-sea-venice.html

Families carried children on their shoulders through the surrounding streets. While some tourists donned thigh-high wellies, others had opted to take off their shoes and wade through the water.

The waters have only topped 150 centimetres five times before in recorded history. In 1966, when floods swept through the country, famously devastating Florence's historic centre, the waters reached 194 centimetres in Venice.