Four Corners S2018E26 - Inside Facebook

Facebook says it's on a mission to be the place where people connect and "bring the world closer together". More than a billion people are on the social networking site every day, posting their thoughts, pictures, and videos.

But alongside the family photos and FOMO inducing holiday videos is content that is truly disturbing.

This British investigation has exposed the inner workings of the social media giant to reveal how and why content moderation decisions are made.