The grueling 26.2 mile course was especially challenging for one particular participant who ran the full marathon blindfolded with a guide.
His name is E.J. Scott and he's slowly going blind. About ten years ago, E.J. was diagnosed with Choroidarema, or CHM, a genetic eye disease that slowly erodes your periphery vision and eventually your central vision.
E.J.'s brother and seven year old nephew have also been diagnosed with the disease. There is no cure.
So E.J. decided he had to take action to raise awareness and funding for CHM research. He's running 12 marathons this year -- one a month -- hoping to raise $12,000 per race.
He has to run each race blindfolded because exposure to sunlight further damages his eyes.
Before the Austin Marathon -- race number 2 -- E.J. met up with seven-time Tour de France winner Lance Armstrong whose Livestrong Cancer Foundation sponsored the event.
"When I read the article in the paper this morning," Armstrong said, "I was like, 'hmmm blindfolded, I'm going to walk over to the coffee pot blind, I mean just cover my eyes.' People take things for granted in life, obviously, Your sight is something that obviously most of us take for granted, all of us take for granted and uh. Think about it, I mean 26 miles, how many steps is that? 5 hours, that's thousands and thousands of steps. I mean we all take a step and see where we're going for the most part all of us. It's admirable, I can't even imagine."
E.J.'s next run will be the Los Angeles Marathon March 18th.