From Wikipedia ....
Code Adam is a nationally-recognized "missing child" safety program in the United States, originally created by Wal-Mart retail stores in 1994. It is named in memory of Adam Walsh, the 6-year-old son of John Walsh, who was abducted from a Sears department store in Florida and was later found murdered in 1981. Today, many department stores, retail shops, shopping malls, supermarkets, amusement parks, and museums participate in the Code Adam program. Legislation enacted by Congress in 2003 now mandates that all federal office buildings employ the program.