Final answer:
Parts of the painting 'The Last Supper' by Leonardo da Vinci were lost or damaged due to various factors such as its location, materials used, and poor restoration efforts.
Step-by-step explanation:
The painting The Last Supper, created by Leonardo da Vinci, has suffered from various damages over the years. Due to its location, materials used, and poor restoration efforts, the painting's condition has deteriorated significantly.
Additionally, a section of the refectory where the painting was displayed was destroyed by a bomb in 1943. As a result of these factors, parts of the painting have been lost or damaged, including approximately 17.5% of the surface.