And finally tonight, would you dance til you dropped for 46 hours, and could you do it to celebrate life? Watch now, as 700 students at Penn state defy exhaustion and sore feet, to use their energy to... See More
And finally tonight, would you dance til you dropped for 46 hours, and could you do it to celebrate life? Watch now, as 700 students at Penn state defy exhaustion and sore feet, to use their energy to light a fire for other kids who need it. ABC's Sara Haines and the students who are "America strong." Don't let that silly hat fool you. I'm ready. Reporter: Allison and Ryan are preparing for a marathon. Stretching a little bit. Yeah. Trying to stretch out. This is the last time we're going to sit for awhile. Reporter: 46 hours, no sleep, no sitting, no coffee. Just dancing. This is Penn state Thon. America's biggest college dance marathon. More than 700 dancers shaking, shimmying, strutting their stuff. All to help kids like 13-year-old Brittany Wagner. Brittany has cancer. Money raised here will help pay for her family's medical costs. After 24 hours -- Can't even move my feet. Reporter: Almost 36 hours in, Allison's legs are swollen. She's losing her voishgs but -- It's not really about us. It's about fighting cancer. Reporter: And 44 hours in, nearly two days after their dance began -- Allison and Ryan are barely hanging on. I mean -- I'm tired. And I am in pain. Tleeshgs three, two, one -- Reporter: And then, it's over. Mission accomplished. $13 million raised and perhaps, more importantly. So happy! Reporter: Brittany is beaming. I love you. Don't ever underestimate the effect you can have on a child's life. Reporter: Dancing with your feet and your heart -- that is "America strong." Sara Haines, ABC news, state college, Pennsylvania. And we celebrate them all and
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