It's a remote corner of the world, but what is taking place there is nothing short of breathtaking.
Xinjiang province is a vast area of deserts and mountains where the ancient Silk Road once ran. Today its Uyghur population is being systematically rounded up with estimates of as many as a million citizens being held in detention.
In this investigation by reporter Sophie McNeill, Four Corners uncovers disturbing evidence of how China is effectively operating the world's largest prison.
