Venice has sunk 24 inches in 300 years, says a new study based on historic paintings. “The study, published in the latest issue of the journal Climatic Change, analyzed eight paintings by Giovanni Antonio Canal, nicknamed Canaletto, (1697-1768) and three by his lesser-known nephew Bernardo Bellotto (1720-1780). Both artists produced their paintings with the help of a portable camera obscura, a lens that projects images onto sketch pads. The trick, described by Leonardo da Vinci 250 years earlier, enabled them to reproduce accurate urban landscapes, complete with the lines of green scum formed by algae left on canal-side buildings by retreating high tides.”