The painting covers the walls inside the Room of Planks at the Sforzesco Castle in Milan, where Leonardo was the court artist for the Duke of Milan, Ludovico il Moro. It depicts trees soaring from the walls to the ceilings.
Workers said the mural's base had been painted and plastered over -- in some cases as many as 17 times, ANSA news agency reported Wednesday. The painting was originally done in 1498.
The initial restoration work requires hand removal of the top layers using scalpels and hammers. Once workers get closer to the original painting it will likely require far more sophisticated methods such as ultrasound scaling, lasers and chemical treatments.