Leaving people behind is an unfortunate part of growing up. We move away, pursue different careers and initiate ourselves into the dark and dangerous contract of marriage. You lose the things you had in common with your childhood friends, until all you have left is an old photo of you all together.
This makes it even more special when old friends do manage to stay in contact. These guys took a photo together when they were 19. They returned to the same place every 5 years to take the same photo. The deepening lines in their faces tell diverging stories, but yet their friendship endures.