Modern times brought a new set of threats, including smog, water pollution, hordes of tourists, and the pigeons.

Officials argue that the pigeons’ highly acidic guano seeps into fissures in thousands of marble monuments and building facades, weakening the structures. In addition, they scratch and peck at the marble, seeking its calcium content as a nutrient, doing further, costly damage.

@ Boston Globe

The beaks shall inherit the earth.