National Missing Children's Day is being observed simultaneously with Memorial Day.
It's held in honor of Etan Patz, who went missing on May 25, 1979. Etan's body was never found. A recent trial in the case ended with a hung jury.
Robert Lowery of the National Center for Missing and Exploited Children says more than 470,000 children are missing across America.
He says children should be empowered to "say no" — and parents should pay attention if something happens that makes a child uncomfortable.