Venice's Grand Canal mysteriously glows fluorescent green, police investigate.

A patch of water in Venice's central waterway turned fluorescent green, prompting an urgent investigation by local authorities. The cause of the color change is unknown, with theories ranging from the release of dye to a protest by environmental activists. Police are examining CCTV footage to determine if the incident was a stunt. The images have reminded many of a 1968 stunt by an Argentine artist who dyed the Grand Canal green to raise awareness of ecological issues.