How fast is Venice sinking? For at least three centuries it’s been going down at a rate of about 8 inches a century. How do scientists know? By looking at the paintings of 18th Century painter Giovanni Antonio Canaletto. The scientists turned to Canaletto because precise measurements of the city’s sea level only date to 1872, while the artist’s works are from the previous century. Canaletto was so true to detail he even painted the dark algae stains on buildings along canal banks, a detail many artists avoided for aesthetic reasons.”