Britain's Prince Harry admits he could "never prepare" himself for the things he saw in Afghanistan.
The 29-year-old Army captain - who underwent two tours of duty in the region in 2007 and 2012 has spoken about the "horrendous" things he saw, such as children killed by roadside bombs and forces lying in the battlefield.
He wrote in The Sunday Times newspaper: "I had never seen it first-hand.
"By 'it' I mean the injuries that were being sustained largely due to improvised explosive devices (IEDs). Loss of life is as tragic and devastating as it gets, but to see young lads - much younger than me - wrapped in plastic and missing limbs, with hundreds of tubes coming out of them, was something I never prepared myself for."
Harry has been busy organising the Invictus Games, which will see teams of injured service personnel from 14 countries compete in sporting events, and says he was "hooked" on creating the competition after meeting competitors from the Warrior Games in America in 2012 and watching the contest in Colorado last year.
He added: "It was one of the most incredible and inspiring things I had ever seen ... some of those competing had been lying in a bed no more than eight months earlier, being told they would never walk again.
"Given the grit and determination they have shown to move beyond their injuries, they would be a fantastic addition to any team."
And Harry has promised spectators of the London event, which takes place next month, they will be in for a thrilling time.
He said: "They strive for perfection every day, so don't think for one second that spectators will get anything less than 150 percent effort from the competitors. Lives will be changed for the better over a weekend and not just for the competitors - believe me!"