A fresco is both a painting done on a wall and the technique used to create such a painting. A fresco is made using pigments mixed with water painted onto a wall when the plaster is still wet. A fresco painted on dry plaster, called fresco secco, is less durable than a true fresco, or buon fresco. Arguably the most famous fresco is on the ceiling of the Sistine Chapel, painted by Michelangelo.