20/20 looks at the story of a teen who goes from being an A student to missing to murdered .
What really happened between a loving mom and a teen football player?
Wildly successful moguls give back, share their secrets with Barbara Walters.
How the explosively popular video-sharing site has changed lives.
The Sixth Sense: Victims track down records showing boyfriend with HIV knew he had virus.
The Sixth Sense: Discover how a dogged detective cracked a mind-boggling mystery.
The Sixth Sense: In prescient letters, two women predicted their own deaths.
Meet a woman who walks on airplanes, a man with arms of steel and more.
A behind-the-scenes look at the pop culture phenomenon of reality television.
ABC News' Charles Gibson sits with us to discuss this special report.
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