About 300 indigenous tribes live deep in Papua's forests, having survived off the grid for thousands of years. We went in search of one of these tribes - the Dani tribe, who are known to be fierce warriors, and who used to practice bizarre age-old rituals that include cannibalism and self-mutilation.

On our journey, we met 73-year-old Yudas in one of the villages perched in Baliem Valley, and heard about how he participated in a tribe killing to avenge his late brother.