Venice police investigate source of bright green liquid in Grand Canal

Speculation climate protesters could be responsible for phosphorescent patch that appeared by Rialto Bridge

Police in Venice are investigating the source of phosphorescent green liquid that appeared on Sunday in the city's Grand Canal, amid speculation it was caused by climate protesters.

Gondoliers could be seen punting through the phosphorescent waters while tourists took photographs of the green patch, from the Rialto Bridge up and along part of the canal.