Painting the Vatican’s Cortile del Belvedere in Milk

Mixed with both slaked lime and natural pigments (in fact, the original cream color used in the 1500s), milk from the Pope’s cows—raised at the papal summer residence, Castel Gandolfo—is being used to paint the Vatican’s Belvedere Castle. This is a centuries-old technique that also happens to align with Pope Francis’ emphasis on environmental protection. To learn more about the process and even the Vatican’s centuries of research on essential oils, head over to CNN.