For most people, the notion of completing a full marathon—26.2 miles—seems insane, if not altogether impossible.

But ultra-runner Alex Anyse isn't most people. And he's planning on competing in an event that's a hell of a lot more than 26.2 miles—all for charity. Anyse is taking on the "Spartathlon," a 153-mile race that starts in Athens and ends in Sparta—to support the Smile Train organization, which provides cleft lip and palate surgeries to children in developing countries.

Check out his interview in the above video.