Most of us will never know the full horrors of combat. Many servicemen and women suffer life-changing injuries, visible or otherwise, while serving their country.
In 2013, Prince Harry saw how the power of sport can help physically, psychologically and socially, those suffering from injuries and illness.
He was inspired and the Invictus Games was born.
This year's games will be held in Sydney.
Invictus Games Participant Ihaka Matairangi spoke to Duncan Garner.
Watch the video.