The Extinction Rebellion group said they used fluorescein dye to color the water.
In Italy, the water of the Canale Grande, the widest waterway in Venice, turned bright green on Saturday.
Behind the seizure were environmental activists who wanted to show their dissatisfaction with the fact that no progress has been made at the UN climate meeting (COP28) organized in Dubai.
Activists from the Extinction Rebellion group also hung ropes with banners on the Rialton Bridge over the Grand Canal.
Water traffic on the Grand Canal was suspended for the duration of the protest.
The Extinction Rebellion group said they used fluorescein dye to color the water, which is non-toxic to the environment.
Mayor of Venice Luigi Brugnaro was not happy about the rapture. He called the activists eco-vandals and demanded that the Italian authorities punish the activists.
The water was also colored in other parts of Italy on Saturday. Among other things, part of the Po river in Turin and part of the Tiber river in the area of Rome turned green.
Reuters