The only widely accepted self-portrait by da Vinci has developed red blotches, fungi, and spots, referred to as "foxing." The small size of the work (it's only 13.2" x 8.5") combined with its extreme fragility has prompted conservators to wonder whether attempting to repair the drawing will actually destroy it further. The jury's still out regarding whether they are going to intervene or not, but as for now, the piece remains in closely monitored storage. [HuffPo]