If you're lucky enough to have a best friend, chances are that you've gone through thick and thin together, but these two remarkable young men have overcome more than most.
After being given just a 2% chance of survival at birth, Odin Frost and Jordon Granberry, both 18, have beaten the odds to attend their graduation together.
Watch the heartwarming footage of Odin and Jordon graduating together below:This came after their parents were given the devastating news that if they managed to survive their early years, they would only do so in a vegetative state.
Now, to mark their graduation, the pair have recreated an adorable picture that was taken of them on their first day at school when they were just three years old.
The pair, who are almost completely non-verbal, struck up a friendship on their first day of school, so this picture is special in more ways than one as it is celebrating 15 years of friendship.

Odin's dad Tim said: "My son and his best friend were both told their survival rate would be around 2 percent, that they'd never walk, and that they'd live in a vegetative state - if they made it past seven years.
"Both walked the stage and graduated. I was on cloud 19. I was so fricking proud of him.
"We just want our kids to be seen, and seen for the beautiful humans they are, and seen for their accomplishments."
Odin's mum Deanda, from Texas, gave birth to him three weeks early with a bleed in the brain and had suffered from preeclampsia when she was pregnant.

At the time of his Odin's birth, doctors weren't sure of his diagnosis, but they warned his parents that his cognitive function wouldn't exceed that of an average seven-year-old and that he would be unable to walk or talk.
However, Odin went much further than doctors expected him to and attended a school for special needs children and it was there that he met Jordon.
"They are fiercely loyal and protective of each other," Tim said.
"They definitely feel a vibe together. If someone comes too close to Jordon, and they don't like the vibe, Odin will go into protective mode.
"Odin will laugh and Jordon will laugh too - it has always been that way.
They have a special connection that I don't know if the outside world would know what was going on."
In addition to attending school, the two boys are able to walk, but they use wheelchairs to help them manage long distances, and while Odin doesn't speak much, he is fully aware of his surroundings and what's going on.

The proud father initially shared the pictures of the pair on Reddit, where they were met with countless supportive messages from strangers.
Tim said: "We're more used to people being mean than being kind.
"People stare in public and kids make fun and the internet is usually one of the most horrible places.
"I was getting ready to defend him but it has just been kindness.
"My wife and I just lay there in bed reading the comments, and we were crying at how beautiful it is."
Congratulations to the two graduates!