In October 2018 BBC journalists exposed a network of hidden detention centres in China, where hundreds of thousands of Muslims have been detained without a trial. But with China denying the claims - how did the team figure out who was telling the truth? The story of how the BBC's China Correspondent John Sudworth investigated starts at 1:02.
BBC My World is a new show for young people around the world, brought to you by executive producers Angelina Jolie and the BBC World Service. We've also partnered with Microsoft Education and BBC Learning to show you how the news is made, fact-check stories and spot fake news.