Christian Alvarado, who is blind, explains why he runs in the Marathon. He has read six books about President Franklin Roosevelt, who had polio.
"He saved the country," Alvarado says. "He helped get us out of a depression. And back then, a lot of people believed having a disability was really an obstacle.
"He didn't let a disability stop him."
See the video that shows how Alvarado competes.
