Three-year-old Madeleine McCann vanished from a Portuguese holiday apartment 16 years ago.
In the intervening years, a huge, costly police operation has taken place across much of Europe.
Madeleine’s parents, Kate and Gerry, say all they have ever wanted is to find their daughter.
Here is the story so far.
On 3 May Madeleine, from Rothley, Leicestershire, is on holiday with her family at the Ocean Club in Praia da Luz, Portugal.
Her parents go for dinner with a group of friends at a restaurant in the complex. Madeleine and her younger brother and sister – twins – stay in the apartment, 100 yards away
The adults had devised a rota system to check on all their children during the evening
When it is the turn of Kate McCann, she discovers her daughter, Madeleine, has gone
Police are called and staff and guests at the complex search for her until daybreak
Border police and airport staff are put on alert and hundreds of volunteers join efforts to find Madeleine in the following days On 12 May, the McCanns say they “cannot describe the anguish and despair” they are feeling.
Portuguese police say they believe Madeleine was abducted but is still alive and in Portugal.
On 26 May, police issue a description of a man seen on the night of Madeleine’s disappearance, possibly carrying a child.
In June, a Portuguese police chief admits vital forensic clues may have been destroyed as the scene was not protected properly.
In July, British police send sniffer dogs to assist the investigation, and inspections of the McCann’s apartment and rental car are conducted.
By August it is 100 days since Madeleine disappeared. Investigating officers publicly acknowledge she may not be found alive.
On 6 September, Portuguese police interview Kate McCann as a witness. On 7 September, detectives make the couple “arguidos” and days later, the McCanns return to the UK. Prosecutors later say there is no new evidence to justify re-questioning them.
Gerry McCann releases a video in November saying he believes his family was watched by “a predator” in the days before his daughter’s disappearance.
2008
On 20 January the McCanns release sketches of a suspect, based on a description by a British holidaymaker of a “creepy man” seen at the resort.
In April, Portuguese police fly to the UK to sit in on interviews conducted by Leicestershire Police of the McCanns’ friends they had dinner with on the night Madeleine disappeared.
On 3 May, one year since the disappearance, Mrs McCann urges people to “pray like mad” for her little girl.
By July Portuguese police say they have submitted their final report on the case. Weeks later, authorities shelve their investigation and lift the “arguido” status of the McCanns.
2009 and 2010
On 3 November, new images of how Madeleine might now look are released.
In March 2010, the McCanns criticise the release of previously unseen Portuguese police files – detailing possible sightings of Madeleine – to British newspapers.
A month later, in April, Gerry McCann says it is “incredibly frustrating” that police in Portugal and the UK had not been actively looking for his daughter “for a very long time”.
In November, the couple sign a publishing deal to write a book about Madeleine’s disappearance.
2011
The McCanns’ book, Madeleine, is released in May.
Prime Minister David Cameron asks the Metropolitan Police to help investigate. A two-year review follows.
2012
Det Ch Insp Andy Redwood, the detective leading the UK review of Madeleine’s disappearance, tells an April broadcast of the BBC’s Panorama his team is “seeking to bring closure to the case”.
A computer-generated image of what Madeleine might look like aged nine is released, a day before Portuguese authorities say they are not reopening their investigation.
2013
In May, UK detectives reviewing the case say they have identified “a number of persons of interest”.
By July, Scotland Yard announces it has “new evidence and new witnesses” in the case and opens a formal investigation.
By October, Scotland Yard detectives say they have identified 41 potential suspects.
A BBC Crimewatch appeal features e-fit images of a man seen carrying a blond-haired child of three or four in Praia da Luz at about the time Madeleine went missing.
Portuguese police reopen their investigation – to run alongside Scotland Yard’s – citing “new lines of inquiry”.
2014
In January British detectives fly to Portugal amid claims they are planning to make arrests.
In June searches in Praia da Luz are carried out, including an area of scrubland situated south-west of the Ocean Club complex. It yields nothing of interest.
A month later, in July, four suspects are quizzed by police but no new developments emerge.
Source: BBC