Russian Ark (dir. Alexander Sokurov)
Filmed in the Winter Palace of the Russian State Hermitage Museum with a cast of thousands, three live orchestras and an army of technicians, Russian Ark is the longest uninterrupted shot in film history, and the first feature film ever created in a single take.
I implore anyone with an interest in beauty, history or films (or best - all three) to see this film. It will break your heart!