(Photo from ANSA) 

ROME – A mysterious phosphorescent green stain appeared in the Grand Canal in Venice on Sunday.

Thoughts immediately went to a climate protest but no group claimed an attack on the iconic waterway.

Those with a longer memory were reminded of a shining green stain that Argentine artist Nicolas Garcia Uriburu put into the canal at the Biennale in 1968 in a piece of performance art to raise environmental awareness.

Samples of the green dye were taken Sunday to establish its make-up and origin. (ANSA)