China's 'armageddon' warning to Australia

In the Northern Territory thousands of US Marines and Australian soldiers are training for battle. It's a war game, but there's a lot at stake amid heightened concern from the Pentagon that China could invade Taiwan before 2027. The United States is even sending nuclear capable bombers here.  Today, Four Corners reporter Angus Grigg on his investigation into how the top end is becoming a major military base for the US and why that could leave Australia vulnerable to attack.  Featured: Angus Grigg, reporter, ABC TV's Four Corners