Every two months, Michelangelo's statue of David, completed in 1504, undergoes a careful cleaning at its home in Florence's Accademia Gallery, where it has resided for over 150 years. His personal restorer, Eleonora Pucci, climbs on a scaffolding for an up-close view -- part of a monitoring and cleaning ritual necessary for the preservation of the Renaissance icon visited by over two million visitors last year.