Etan Patz trial
New York Police Department spokesman Paul Brown holds an original missing poster of Etan Patz during a news conference near a New York City apartment building, where police and FBI agents were searching a basement for clues in the boy's 1979 disappearance, in New York, April 19, 2012. Reuters

May 25 is marked as the National Missing Children's Day, which was first proclaimed by former President Ronald Reagan in 1983. A series of high-profile missing children cases, including the Etan Patz case, inspired the start of this day.

Etan disappeared on May 25, 1979, while walking to a bus stop alone for the first time ever. It was the last time he was seen and the child's body was never found. His disappearance changed the way kidnappings were investigated in the United States. The anniversary of his disappearance was later marked as National Missing Children’s Day.

It took 33 years for a suspect to be arrested for Etan’s disappearance. In 2012, police arrested Pedro Hernandez, who worked at a convenience store near the family’s Prince Street home. Hernandez’s brother told police he had mentioned killing a boy to a prayer group in the summer of 1979.

Read: Who Is Etan Patz?

According to the Office of Juvenile Justice and Delinquency Prevention (OJJDP): "Missing Children’s Day is dedicated to encouraging parents, guardians, caregivers, and others concerned with the well-being of children to make child safety a priority. It serves as a reminder to continue our efforts to reunite missing children with their families and an occasion to honor those dedicated to this noble cause."

Approximately 800,000 kids are reported missing each year in the country, according to the National Center for Missing and Exploited Children.

More than a decade after National Missing Children's Day was designated by Reagan, the International Centre for Missing & Exploited Children (ICMEC) and the U.S.'s National Center for Missing & Exploited Children (NCMEC), the Global Missing Children’s Network (GMCN) launched a joint venture in 1998 to mark May 25 as the International Missing Children's Day.

The 23 member countries participating in the venture along with the U.S. are Albania, Argentina, Australia, Belarus, Belgium, Brazil, Canada, Germany, Greece, Hungary, Ireland, Italy, Mexico, the Netherlands, New Zealand, Poland, Romania, Russia, Serbia, South Africa, South Korea, Spain, and the United Kingdom.

"The main purpose of International Missing Children's Day is to encourage everyone to think about children who remain missing and to spread a message of hope by releasing a balloon," states the Help Bring Them Home Campaign formed in 2001.

On Tuesday, Jeffrey S. Sallet, Special Agent in Charge (SAC) of the Federal Bureau of Investigation’s (FBI) New Orleans Field Office, reaffirmed the FBI’s continuing support of National Missing Children’s Day.

"In 1932, the FBI was given jurisdiction under the “Lindbergh Law” to immediately investigate any reported mysterious disappearance or kidnapping involving a child of “tender age”—usually 12 or younger. However, the FBI can become involved with any missing child under the age of 18 as an assisting agency to the local police department. There does not have to be a ransom demand, and the child does not have to cross the state lines or be missing for 24 hours. Research indicates the quicker the reporting of the disappearance or abduction, the more likely the successful outcome in returning the child unharmed," FBI New Orleans wrote in a statement.

FBI New Orleans shared a link of some missing children cases.