The number of marathon finishers in the US this year will likely eclipse last year, when an estimated 541,000 people ran a marathon according to Runners World. Why are so many athletes opting to run 26.2 miles? There's plenty of scientific reasons to do the regular exercise that's required to train for it. But after so many miles, the answers get shorter and more personal. Here's what it looks like from inside a mass of 50,000 other runners.
Clarification: In the video, I present an extremely compressed version of the full story.