(CNN)Here is a look at missing children in the United States. There are several different types of missing children: runaways, family abductions, lost or "thrown away," and non-family abductions. Recent advances in technology, communications through public alerts and greater cooperation from law enforcement have helped solve many cases quickly.
According to the FBI's National Crime Information Center (NCIC) Missing Person File, there are 88,040 active missing person records, of which juveniles under the age of 18 account for 33,706 (38.3%) of the records. (as of December 31, 2016)
"AMBER (America's Missing: Broadcast Emergency Response) Alerts are emergency messages broadcast when a law enforcement agency determines that a child has been abducted and is in imminent danger. The broadcasts include information about the child and the abductor, including physical descriptions as well as information about the abductor's vehicle - which could lead to the child's recovery."
This list represents notable and/or recent cases.
February 1, 2004 - Eleven-year-old Carlie Brucia is kidnapped on her way home from school in Sarasota, Florida. The abduction is captured on surveillance video at a car wash.
May 16, 2005 - Nine-year-old Dylan and eight-year-old Shasta are reported missing from their home after their mother, her boyfriend, and their older brother are found murdered in their Coeur d'Alene, Idaho home.
January 13, 1996 - Nine-year-old Amber Hagerman is abducted as she rides her bike in a parking lot near the home of her grandparents in Arlington, Texas.
May 8, 2005 - Laura Hobbs and Krystal Tobias are reported missing from their homes in Zion, Illinois.
October 2002 - Eleven-year-old Shawn Hornbeck is kidnapped while riding his bicycle to a friend's house near his home in Richwoods, Missouri.
October 4, 2011 - Ten-month old Lisa is found to be missing from her crib by her father, Jeremy Irwin, when he returns home from work between 3 am and 4 am in Kansas City. Also missing are the family cell phones.
July 29, 1994 - Seven-year-old Megan Kanka is lured by Jesse Timmendequas, a neighbor and convicted sex offender, into his house across the street from her own house in Hamilton Township, New Jersey, where he sexually assaults and strangles her. Her body is found in a park the next day.
October 1, 1993 - Twelve-year-old Polly Klaas is abducted during a slumber party at her home in Petaluma, California.
February 24, 2005 - Nine-year-old Jessica Lunsford is discovered to be missing from her bedroom in Homosassa, Florida.
February 22, 1985 - Eight-year-old Cherrie is kidnapped on her way home from school in Winfield Township, Pennsylvania.
May 25, 1979 - Six-year-old Etan Patz disappears in the SoHo section of New York City while walking to the school bus stop alone for the first time.
December 17, 2011 - Justin DiPietro reports his 20-month-old daughter Ayla Reynolds is missing from their home in Waterville, Maine.
July 15, 2002 - Five-year-old Samantha Runnion is abducted outside a Stanton, California apartment complex while playing with a friend.
June 5, 2002 - Fourteen-year-old Elizabeth Smart is abducted from the bedroom of her home in the Arlington Hills neighborhood of Salt Lake City.
February 2, 2002 - Seven-year-old Danielle van Dam is discovered missing from her home in suburban San Diego.
July 27, 1981 - Adam Walsh is abducted from a mall near his home in Hollywood, Florida. His mother had let him look in the toy department at Sears while she looked for a lamp. When she returned, Adam was missing.
April 2002 - Florida's Department of Children and Families (DCF) discovers four-year-old Rilya Wilson is missing from the home of her caregiver, Geralyn Graham. DCF did not learn of her disappearance until well after she disappeared. Case reports were falsified to show Wilson's foster home had been visited.