On their first morning in New York City, Polly and Jamie Kemler of suburban Boston and their 9-year-old twins, Ian and Amelia, rushed toward a crowded subway car. Jamie, Polly, and Amelia made it in. Ian was left behind on the platform.

"I started banging On the doors frantically shouting `Ian, Ian, Ian!'" recalls Polly. "I was trying to get the doors open with my hands. Then we left, leaving forlorn, shy, and suddenly very little Ian behind."

Thanks to helpful subway workers and commuters, the Kemlers were soon reunited and set out again for the Statue of Liberty. This time, they got off to a safer start.

"Once we retrieved Ian, we went over all kinds of particulars," says Polly. "And we spent the rest of the time making the kids hold our hands."

Whenever traveling with children, safety begins before you leave your house. Study a map of your destination online or in a brochure; locate help centers and pick an emergency meeting spot.

"A little planning up front will keep you from having disasters later on," says Nancy McBride, of the National Center for Missing and Exploited Children.

SET NEW RULES