What's your chance of reaching a very old age? That can depend on when you were born and even where you live. Click to find out more.
Interactive: How the body ages
Why do we get wrinkles, gray hair and stiff joints as we grow older? Click to learn about the aging process.
How celebrities are aging
We asked Dr. Tony Youn, a Michigan-based board-certified plastic surgeon, to weigh in on what work, if any, celebrities may have had done. (Youn hasn't treated any of those featured.)