This rare film tells the strange, disquieting and protracted story of the restoration of Leonardo da Vinci’s famous masterpiece, The Last Supper. Some say the results of the restoration are glorious. Others have called them tragic. Da Vinci’s famously fragile fresco was always going to be a challenge for its secretive Italian restorers. No one, however, could have foreseen how problematic and strange their task would become. Marked by a series of extraordinary mishaps, mistakes, and miscalculations, the incredible restoration is hilarious to watch but may have resulted in the loss of a masterpiece.

• Documentary