Police are probing why the water in one of Venice's famous canals has turned fluorescent green.
Environmental authorities are undertaking tests to get to the bottom of the mystery in the city's famed Grand Canal.
Governor of the Veneto region Luca Zaia posted a picture of the bright liquid near the Rialto Bridge on Sunday.
It showed a sea of green with theories ranging from the release of dye to a protest by environmental activists. The Volgalonga regatta is taking place this weekend.
Traditional gondoliers continue to punt through the phosphorescent waters as confused tourists search for answers from locals.
Italian media are reporting that police are examining CCTV to determine the cause.
It is not the first time the Grand Canal has been turned green.
Back in 1968, in a stunt to promote ecological awareness, Argentine artist Nicolás Garcia Uriburu dyed the waters during the 34th Venice Biennale.
The region’s president, Luca Zaia tweeted. "This morning in #CanalGrande of #Venezia a patch of phosphorescent green liquid appeared, reported by some residents near the Rialto Bridge.
“The prefect has called an urgent meeting with the police to investigate the origin of the liquid."
Last year it was revealed that Venice is to start charging tourists to visit the famous city in a world first to cut overcrowding.
In an effort to stem the throng of visitors from around the world, from January it is going to become the first city in the world to charge people to visit.
It will charge day-trippers between three to ten Euros (£2.60 to £8.60).
The exact prices depend on the season and whether they were booked in advance and tourists who fail to show the QR code will face a massive fine of €300 (£260).
Prices would also vary according to the number of visitors with the more requests there are, the higher the entry costs.
There are set to be exceptions to the upcoming fees. This includes children aged under six, people with disabilities, and people with homes or timeshares in Venice, as long as they pay council tax.
The fees are set to come into action from January 16, 2023, making it the first city in the world to charge an entrance fee.
The city long referred to as ‘La Serenissima’ (The Most Serene) is clearly no longer as peaceful as Venetian complaints have reached boiling point.
