The Solution to Venice's Mysterious Green Canal Revealed.

The recent transformation of a section of Venice's Grand Canal to fluorescent green was caused by the non-toxic substance fluorescein, used for testing wastewater networks, according to the regional agency for environmental prevention and protection of Veneto. Police investigated whether it was a protest by climate change activists, but the substance was found to be harmless. The Grand Canal had previously turned green in 1968 as part of a stunt to promote ecological awareness.