Some people are just super talented. A few summers back I was at a 5k race with some friends. One of them asked me if I'd met "so-and-so" who'd ran the race and then another friend went on to say that "so-and-so" was really fast and had run 2:30 or so in the marathon. I thought it was interesting but, in the back of my mind I was thinking "2:30!? Really!? Maybe they meant 3:30."
Any how, we were milling around the finish and a friend grabbed me and introduced me to this guy that was probably 5'9" or so and was well over 200. Come to find out this was the guy that'd been talking about that had run "2:30." Now, I was really interested. We started to talk about training and I asked him a bunch of questions so I could go home and look stuff up because the whole time I was thinking "There's no way this guy ran 2:30." He seemed pretty knowledgeable and admitted to gaining some weight since his running days but, it had been rather recent that he'd ran the time.
In any case, I went home and look it up. Everything checked out. The guy had ran low 2:30s and I was floored. There are plenty of super talented people out there. Every year I run a single marathon that I hope to be able to hit around 3:00. I'm always amazed by the number of people that can run sub 3:00.