Venice’s Grand Canal Turned Bright Green This Weekend — See the Photos

Authorities have identified the green substance as a non-toxic chemical, likely purposefully poured into the canal.

<p>Italian Firefighters (Vigili del Fuoco) / Handout/Anadolu Agency via Getty Images</p>

Italian Firefighters (Vigili del Fuoco) / Handout/Anadolu Agency via Getty Images

Venice’s Grand Canal mysteriously transformed into a bright shade of green on Sunday morning — and authorities just found out the cause .

Seen near the city's Rialto Bridge, the vibrant hue spread throughout the day and was reported to be caused by a non-toxc chemical identified as fluorescien, according to CNN.

The chemical is often used in construction projects to help pinpoint the flow of leaks, environmental experts said. However, typically a spoonful of the dye is used, whereas it appears as if at least one kilogram (about a 1/4 of a gallon) was deposited into the Italian canal this weekend.

"I find it hard to believe that it was an incident... and that a kilo of fluorescein was casually released into the canal," Maurizio Vesco of the Regional Agency for Environmental Protection told local Italian outlet La Repubbica, per the BBC.

<p>Stringer/Ansa/AFP via Getty Images</p>

Stringer/Ansa/AFP via Getty Images

No group has come forth to take responsibility for planting the patch of green water, but officials believe it may be a stunt performed by environmental activists, with Luca Zaia, the president of the region of Venice, suggesting to CNN copycat acts may follow.

But there's a chance that Sunday's act itself was already a copycat incident. After all, the same substance was put into the Venetian waters back in 1968 by Argentine artist Nicolás García Uriburu to shine a light on environmental concerns during the 34th Venice Biennale. According to the Met Museum, his act “transformed the landscape of the Italian city for the course of one day, with its waters fluorescent green until the low tide made the dye gradually disappear.”

While García Uriburu's stunt took place during the Biennale focusing on art, this year's Biennale focuses on architecture, and kicked off May 20 and will run through Nov. 26.

More testing will be conducted this week on the green substance, and officials are investigating various leads who may be behind the act.

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