Twenty years have passed since two gunmen stormed Columbine High School and carried out what became the first mass campus shootings in U.S. history.

And while sadly it wasn't the last, the journey of some of the survivors offers hope that although such incidents do represent a dark chapter in the students' lives, they do not come to define their entire stories.

Here, the DailyMail.com tells the two decade journey of some of the courageous students on April 20, 1999, who went from the depths of depression to finding happiness - and how they managed to do it.

Journey: Twenty years have passed since two gunmen entered Columbine High School and carried out what was the first incident of a mass campus shootings in the U.S. And while sadly it wasn't the last, the journey of some of the survivors offers hope that although such incidents do represent a dark chapter in students' lives, they do not come to define their entire stories

Patrick Ireland, 27, a successful financial adviser

The entire nation watched transfixed as 17-year-old Patrick Ireland desperately threw himself from a Columbine High School window into the arms of SWAT team officers Donn Kraemer and John Ramoniec.

Gunned down and left for dead, Ireland crawled on his stomach to a window and climbed out to safety, bringing a brief moment a light in an otherwise dark day.

Ireland was paralyzed down his right side, bleeding profusely and falling in and out of consciousness, but somehow found the will to not only survive but to piece his life back together after that dark day in April 1999.

Ireland said reaching the window was his only chance of survival and said he felt confident someone would be there waiting to catch him.

He was in the library with a friend when the guns started going off. When he tried to help his wounded classmate Makai Hall, he was blasted by Dylan Klebold from 15 feet away with a sawed-off double-barreled shotgun.

Grueling physio: Ireland puts his peak athletic conditioning down as a reason he was able to recover so far and go on to be return for his senior year, go on to study finance at Colorado State University and meet the love of his life on his very first day of college

But for more than three hours, against all odds, Ireland dragged his body towards the window - until he felt the cool air and somehow hoisted himself outside.

Once emergency services had him he was rushed to St Anthony's Central Hospital where doctors battled to save his life.

One of the gunshots had penetrated the left hemisphere of his brain which caused right-sided paralysis and severe damage to his brain's language center.

Ireland also suffered a second head wound and a shattered right foot. But as doctors won the battle save his life, the long road to recovery really began.

Friends would ask him about the ordeal but his sentences would not make sense when he replied. Over seven months he endured grueling therapy where he learned how to walk, talk, read and write again.

Ireland attributes his athletic conditioning as a reason he was able to recover so fast and go on to be return for his senior year, then study finance at Colorado State University where he met the love of his life on his very first day of college.

Now a successful financial adviser with a young family, Ireland uses public speaking to pass on the message that hard work and perseverance can move mountains.

Chilling: The entire nation watched transfixed as 17-year-old Patrick Ireland desperately threw himself from a Columbine High School window into the waiting arms of SWAT team officers Donn Kraemer and John Ramoniec

Austin Eubanks, 37, a father-of-two and motivational speaker

Eubanks was in the library with his best friend Corey DePooter when the gunmen began their chilling murderous rampage. DePooter suffered life-ending injuries but Eubanks, struck twice, was able to survive by pretending to be dead.

In the aftermath of the shooting, Eubanks was prescribed powerful painkillers that not only numbed the pain of his wounds, but numbed the agony of his loss.

Over the course of a decade, Eubanks would spiral into a life of alcohol and opioid dependency, surviving on a cocktail of high dose painkillers to block out the dark thoughts that were consuming him. His marriage failed, he entered rehab twice to no avail and continued falling further into addiction.

One day in 2011, twelve years on from the horrible events, Eubanks woke up and found himself in a prison cell. He had dosed himself into oblivion and did not remember the night before. That, he decided, was the last time he would allow himself to be defined by Columbine and entered rehab – for fourteen long months.

There he began to go through the stages of grief he should have gone through at the time but couldn't because of the drugs. He has been in recovery ever since and now tours the country giving motivation talks and advice to those going through a similar struggle.

His inspirational story has resulted in him giving Ted Talks, working for non-profits and turning his life around entirely – finding happiness in life, and with his two young sons.

Just a kid: Austin Eubanks was just a 17-year-old junior when the sound of gunshots began to ring out through the hallways of Columbine High School in Colorado, changing his life and the lives of every single person at the school that day

Noel Sudano, 37, a guidance counselor at Columbine High School

Noel was another young teenager at the school when the sound of gunshots started to reverberate through the school hallways.

Like many of her peers she sought shelter at a friends house and was thankfully not a witness to the attacks that day. But that hasn't changed how affected she was by the awful events twenty years ago.

In fact, as an adult she returned to the school as a guidance counselor to offer help and support to the the next generation of students.

'It's weird, right?' Sudano told media. 'I think that it just felt like a calling to me. It felt like an opportunity for me to serve the community that did so much to wrap its arms around us on such a horrible day.'

She says coming back has also helped her process what she went through.

'It helps me to reclaim some of the emotions that I have towards Columbine,' she said,

'Because now, I can say that this is a place of community and love and health and joy. And when I finished high school, it didn't necessarily feel that way.'

Noel was another young teenager at the school when the sound of gunshots started to reverberate through the school hallways. As an adult she returned to the school as a guidance councillor to offer help and support to the the next generation of students.

Frank DeAngelis, 64, former Columbine High School principal, now retired

One of the most resonant images surrounding the Columbine shooting actually came in the aftermath of the event. Distraught principal Frank DeAngelis bravely consoling young students while holding red and white roses symbolizing peace.

The educator is described as a national treasure, and his office is littered with letters from various presidents and senior figures who recognize the tremendous courage and leadership he demonstrated in the wake of the attacks,

DeAngelis remained at the school for another fifteen years after the attack, and even carried the Olympic torch in 2002 for the Salt Lake City winter games.

The reason for his tenure was because of one noble promise. That he would stay at the helm until every student who had been in school than unimaginable day had graduated.

Then, he expanded his pledge, remaining at his post until every single local child who had been in class that day, down to preschoolers, had earned their diploma.

But despite his perseverance, the former educator says he is still learning to move on from the day.

Today he travels the country liaising with principals and communities that have fallen victim to the scourge of school shootings.