One of the inherently wonderful things about motion pictures is that there are so many out there, and it's up to we - the movie-goers - to seek out the ones that appeal and resonant with us. There are no laws or regulations forcing us to watch any particular movies, after all (though your annoying movie buff friend might beg to differ), and everybody is entitled to watch whatever they want, when they want, depending on their taste. That said, if you had to pick one singular movie that absolutely everybody on Earth was required to watch, what would it be? Selecting just one movie for such a purpose is insanely difficult, of course; how do you pick a movie that appeals to everyone on the planet? How can you justify your pick? Is it possible to choose just one movie that truly and actually deserves to be seen by the entire population of the world? The answer to that question is likely impossible to find, of course, but it doesn't mean it isn't an interesting one to ponder. Does the one movie need to be spiritual? Does it need to address real world issues, or can it be fantastical? What themes should such a movie embrace? Our pick goes to the transcendent French documentary, Shoah - one which is often hailed as the greatest documentary of all-time. As one of the longest films ever made (it runs at around 10 hours), Claude Lanzmann's timeless and stunning work explores the holocaust in its entirety, presenting viewers with the testimonies of survivors, witnesses and perpetrators in what was one of the greatest travesties of the 20th century. For human beings everywhere, it is a chronicle of genuine evil, and in its haunting, painful recollections, feels like a truly essential work. Which movie would you pick? Let us know in the comments section below.