What we know about global security 25 years on since 9/11

It's been 25 years since nearly 3,000 people were killed in the September 11 attacks, which triggered the US-led War on Terror and drew Australia into wars in Afghanistan and Iraq. A quarter-of-a-century later, former prime minister John Howard and security experts say the terrorist threat has evolved into something far more complex.It's been 25 years since nearly 3,000 people were killed in the September 11 attacks, which triggered the US-led War on Terror and drew Australia into wars in Afghanistan and Iraq. A quarter-of-a-century later, former prime minister John Howard and security experts say the terrorist threat has evolved into something far more complex.