A survivor of the Columbine High School massacre reflects on the shooting 20 years on

On the 20th anniversary of the Columbine High School massacre, a miracle survivor who sustained three gunshot wounds throughout the attack has opened up about his ordeal.

On that dark day, the world watched on as Patrick Ireland, known as the "boy in the window" dragged himself to safety to escape the gunfire, and threw himself out of a window into the arms of waiting SWAT officers Donn Kraemer and John Ramoniec.

Patrick Ireland dragged himself to a window to get to safety. Photo / Supplied

Ireland was falling in and out of consciousness and was paralysed down his right side when he managed to escape.

Now, two decades on, he has pieced his life back together and has opened up about the horrific ordeal.

"After I was shot, I blacked out and was unconscious through most of the mayhem. It was a blessing in disguise. It saved me from a lot of traumatic memories," the father-of-three told the Mirror.

Patrick with his wife Kacie. Photo / Supplied

"We were all shot fairly early on in the library,' Ireland said. 'We heard their shots and the throwing of pipe bombs as they got closer. It was harrowing," he said.

Ireland recounted that getting himself to the window was the only chance of surviving.

On April 20 1999, two students of Columbine High School Dylan Klebold, 17, and Eric Harris, 18, began a murderous rampage leaving 12 students and one teacher dead.

Ireland was in the library when he first heard gunshots. When he tried to help his wounded classmate, he was blasted by Klebold from 5 metres away with a double-barrelled shotgun.

For more than three hours, Ireland dragged his body towards the window — where he was confident someone would be waiting.

Ireland was immediately rushed to hospital where doctors battled to save his life.

One of the gunshots he sustained had pierced the left hemisphere of his brain, causing paralysis and damage to his brain's language centre.

Ireland also endured a shattered right foot and a second head wound.

Although doctors won the battle save his life, the road to recovery began when he left the hospital.

For the next seven months he endured intense therapy where he had to learn how to walk, talk, read and write again.

Now, Ireland is a successful financial Adviser with three young children, and uses public speaking to pass on inspirational messages that hard work and perseverance can get you anywhere.

Ireland with his wife Kacie, his two daughters Kennedy, nine and Kensington, four, plus their baby son Keene. Photo / Supplied

"Those of us who choose to be victors can achieve the goals we set out for ourselves," he said

Today, the miracle survivor only bears one physical marker from the ordeal, his limp which he has never recovered from.

As the anniversary of the horrific ordeal approaches, he remains upset that the attack on his school wasn't the last of its kind.

Finishing on a confident note, the survivor, said: "I was so determined not to let my shooters win. I believe the world is still good at heart. People need to hold on to that.

"Evil will not win. There are too many good people in the world."