British girl Madeleine McCann vanished aged three from a Portuguese holiday apartment in May 2007.
A Portuguese police investigation which ran until July 2008, and a continuing high-profile international campaign run by her parents Kate and Gerry, have failed to locate her.
At one stage, Mr and Mrs McCann, of Rothley, Leicestershire, and another British man - Robert Murat - were considered formal suspects in the case, but all three were later cleared.
She was holidaying with her parents and her younger twin siblings.
Mrs McCann is understood to have told police that after tucking the children up in bed Madeleine - who was wearing pink pyjamas with the words "Sleepy Eeyore" on them - said: "Mummy, I've had the best day ever. I'm having lots and lots of fun."
It is known Mr and Mrs McCann then went for dinner with a group of friends, at a tapas restaurant 100 yards from the apartment.
Their party - since dubbed the "tapas seven" - included fellow medics Matthew Oldfield, Russell O'Brien, David Payne and Fiona Payne.
Also present were Rachael Oldfield (married to Matthew), Jane Tanner (partner of Russell O'Brien) and Diane Webster (Fiona Payne's mother).
Leaks from the investigation suggest the McCanns arrived for dinner at 2035 local time that evening, according to their friends.
At 2105 Mr McCann went to check on the children, followed by Dr Oldfield, they said.
Ten minutes later, having left the table to check on her own children, Jane Tanner says she saw a man carrying a child, close to the McCanns' apartment
At 2200 Kate McCann checked on her children.
Madeleine was gone.
Mrs McCann told police that when she went to the apartment she found the outside shutter and window to Madeleine's room had been opened and her daughter was missing.
Mrs McCann said police were called within 10 minutes of finding her daughter gone.
Guilhermino Encarnacao, director of the judicial police in the Faro region, said officers arrived within 10 minutes of being alerted, and an investigation unit began work within 30 minutes
The manager of the Mark Warner resort in Portugal, John Hill, said about 60 staff and guests at the complex searched until daybreak for the little girl, while police notified border police, Spanish police and airports.
They were joined in their hunt by hundreds of volunteers in the following days.
5 May: As the search for Madeleine continues, her parents issue a statement to say they "cannot describe the anguish and despair" they are feeling at their daughter's disappearance.
12 May: Mr and Mrs McCann make a fresh appeal for help on their daughter's fourth birthday.
15 May: British-born Robert Murat is made an official suspect - or "arguido" - following a search of his mother's villa. Casa Liliana is 150 yards from the apartment where Madeleine went missing.
26 May: A description of a man seen on the night Madeleine went missing "carrying a child or an object that could have been taken as a child" is issued by police.
30 May: The McCanns meet the Pope at a general audience in Rome at the start of a "European tour" to raise awareness of Madeleine's disappearance.
6 June: A German reporter asks the McCanns how they feel about the fact that "more and more people seem to be pointing the finger" at them, during a press conference in Berlin.
12 June: Mr and Mrs McCann arrive back in Portugal following their European tour.
17 June: Chief Inspector Olegario Sousa admits vital forensic clues may have been destroyed in the hours after Madeleine's disappearance, as the scene was not protected properly.
10 July: Formal suspect Robert Murat re-questioned
Late July: British sniffer dogs fly out to Portugal. Keela, who can detect minute quantities of blood, and Eddie, who is trained to detect dead bodies, work in the apartment and several cars, including the hire car the McCanns rented 25 days after Madeleine disappeared.
6 August: Police fail to find any new evidence after a search at the home of Mr Murat following a two-day search, the BBC understands.
7 August: Forensic tests are carried out in a Birmingham lab on suspected traces of blood found by sniffer dogs in Madeleine's apartment.
11 August: Police in Portugal acknowledge for the first time that, in light of new evidence, Madeleine may be dead. Chief Inspector Sousa adds that Mr and Mrs McCann are not being considered as suspects following newspaper speculation that they are under suspicion.
24 August: Police say they still have doubts over how Madeleine disappeared and whether she will ever be found.
31 August: The McCanns launch a libel action against Portuguese newspaper Tal & Qual which claimed "police believe" they killed their daughter. The McCanns say they are "deeply hurt" by the allegations.
6 September: Portuguese police interview Kate McCann for 11 hours as a witness in the presence of her lawyer. Separately, Portuguese detectives confirm they have the partial results of forensic tests by a UK laboratory.
7 September: Madeleine's mother is declared an official suspect and fears she could be charged, friends say. Gerry McCann is also named as a formal suspect following more questioning. Later, a family representative says officers believe they have found traces of Madeleine's blood in the McCanns' car, hired 25 days after she vanished.
9 September: Kate and Gerry McCann return home to Rothley, Leicestershire.
10 September: Police papers detailing the inquiry into Madeleine's disappearance are passed to Algarve-based prosecutor, Jose Cunha de Magalhaes e Meneses. In Leicestershire, police and social services meet to discuss the case.
11 September: In his internet blog, Gerry McCann says he and his wife Kate face an "unbearable" situation.
Portuguese police play down reports that DNA evidence with a 100% match to Madeleine was found in her parents' hire car.
A statement is made outside the prosecutor's office in Portimao, saying he had received the files detailing the inquiry into Madeleine's disappearance and decided they should go before an instructional judge.
The judge has 10 days to make a decision on the files' contents.
19 September: Portuguese prosecutors rule there is "no new evidence" in police files to justify re-questioning Gerry and Kate McCann.
9 October: A new police chief is appointed to take over the Portuguese inquiry.
Paulo Rebelo, deputy national director of Portuguese police, replaces Goncalo Amaral, who was removed apparently for criticising UK police. New police chief for McCann case
30 October: The fighting fund set up to find Madeleine was used to pay the McCanns' mortgage, it is disclosed.
1 November: Gerry McCann returns to work, as a consultant cardiologist, two days before the six-month anniversary of his daughter's disappearance.
26 September: A photograph taken by a Spanish tourist in Morocco is examined by experts, amid suggestions a girl in the picture could be Madeleine. Reporters later claim that the girl is in fact a Moroccan five-year-old.
16 November: Jane Tanner, one of the "tapas seven", tells the BBC's Panorama programme she saw a man carrying a child 45 minutes before Madeleine was discovered missing.
18 November: Gerry McCann, in a personal video, speaks of his belief that his family was watched by "a predator" in the days before his daughter's disappearance.
22 December: Kate and Gerry McCann send a Christmas message to Madeleine in a video appeal for information.
20 January, 2008: The parents of Madeleine McCann release sketches of a man they believe may have abducted their daughter.
The drawings are based on a description by a British holidaymaker of a "creepy man" seen at the resort.
19 March: The Express Newspaper group pays the Find Madeleine campaign £550,000 and publishes apologises to the McCanns for suggesting they were responsible for her death.
7 April: Portuguese police fly to the UK to sit in on interviews conducted by Leicestershire Police of the so-called "tapas seven".
8 April: Kate and Gerry McCann are asked by Portuguese police to take part in a reconstruction of the night their daughter disappeared.
10 April: Kate and Gerry McCann address the European Parliament in Brussels, calling for an EU-wide alert system for abducted children.
13 April: It is revealed Robert Murat, who along with the McCanns was also an official suspect in the case, is to sue some British-based newspapers over allegedly libellous stories.
14 April: Portuguese police deny leaking details of statements given by the McCanns early in the investigation.
Spanish television broadcasts quotes, including some made by Mrs McCann, supposedly telling officers that Madeleine had been upset the night before she disappeared that her mother had not come to her when she cried.
Late April: In the run-up to the first anniversary of Madeleine's disappearance the McCanns give a series of television and radio interviews and speak of their year of "purgatory".
2 May: The parents of Madeleine McCann urge anyone who spoke to police about her disappearance to contact them.
3 May: Kate McCann asks churchgoers to pray for her daughter on the first anniversary of her disappearance.
7 May: The Portuguese police chief criticised for his handling of the Madeleine McCann case has resigned, says the Ministry of Justice.
14 May: A judge overseeing the Madeleine McCann investigation extends judicial secrecy in the case.
27 May: A reconstruction of the night Madeleine McCann disappeared will not go ahead after the "tapas seven" declined to take part.
23 June: Madeleine McCann's parents take to the High Court an attempt to get police files on their daughter released.
1 July: Portugal's attorney general Fernando Pinto Monteiro says no decision has been taken on the Madeleine McCann investigation, after local media report that police will close it owing to lack of evidence.
But Portuguese police have submitted their final report on the case, which the attorney general says "will be the object of careful analysis and consideration".
7 July: Leicestershire police agree to release files on the case to Mr and Mrs McCann, who had earlier dropped a High Court bid to force the release of evidence.
15 July: British expat Robert Murat accepts a £600,000 damages settlement over allegations in 11 UK newspapers that he was involved in the disappearance of Madeleine McCann.
21 July: Portugal's attorney general Fernando Jose Pinto Monteiro announces that the police investigation into her disappearance will be shelved. All three suspects have their "arguido" status lifted.
A Portuguese judge grants an injunction temporarily banning sales and further publication of a book by former police detective Goncalo Amaral, Maddie: The Truth about the Lie, which was originally published in July 2008. Mr Amaral had been removed as head of the investigation into Madeleine's disappearance after criticising the involvement of British police.
21 October: Shirts emblazoned with pictures of Madeleine are handed out ahead of Everton FC's Europa League tie with Portuguese team Benfica in Lisbon. The words "We're Still Looking For You" are printed on them.
3 November: A one-minute video message - produced in seven languages - is launched by Britain's Child Exploitation and Online Protection Centre, showing new images of how the girl might look more than two years older.
13 December: Gerry and Kate McCann return to Praia da Luz, the resort they were staying at when Madeleine disappeared, while visiting Portugal for a court case over a book claiming she is dead.
28 January, 2010: A video of the McCann's search for Madeleine is shown at a fund-raising event in London in January to mark the 1,000th day since Madeleine's disappearance.
February: The Portuguese former detective fails to overturn a ban on his book about Madeleine. Gerry McCann says new information was not being followed up by Portuguese police.
28 April: Near the third anniversary of Madeleine's disappearance, Gerry McCann says it is "incredibly frustrating" that police in Portugal and the UK had not been actively looking for Madeleine "for a very long time".
6 March: The McCanns criticise the release of previously unseen Portuguese police files on their daughter's case to British newspapers. The 2,000-page dossier details dozens of possible sightings of Madeleine since she disappeared.
2 May: The McCanns release a video online which shows the couple trying to find their missing child over the past three years. It was originally shown in January.
May: The McCanns back the Child Rescue Alert (CRA) scheme in the UK and want Europe-wide co-ordination.
August: Kate and Gerry McCann hold private talks with Home Secretary Theresa May.
October: A court in Lisbon overturns a ban on the book Goncalo Amaral in which he questioned the couple's accounts of their daughter's disappearance.
November: The McCanns sign a publishing deal to write a book about their daughter's disappearance. They also launch a petition calling for a full review of the case by the UK and Portugal.
3 May, 2011: The McCanns mark the fourth anniversary of Madeleine's disappearance with family and friends.
12 May: In an open letter in the Sun newspaper, the McCanns ask the prime minister to launch an "independent, transparent and comprehensive" review of all information relating to the disappearance of their daughter.
They publish a book, entitled Madeleine, which the couple hope will prompt people holding vital information about what happened to Madeleine to come forward.
Sale proceeds will go towards the Find Madeleine fund.
13 May: Prime Minister David Cameron writes to the McCanns telling them the home secretary will be in touch to set out "new action" involving the Metropolitan Police.
A Portuguese police investigation which ran until July 2008, and a continuing high-profile international campaign run by her parents Kate and Gerry, have failed to locate her.
At one stage, Mr and Mrs McCann, of Rothley, Leicestershire, and another British man - Robert Murat - were considered formal suspects in the case, but all three were later cleared.
The disappearance
Madeleine McCann went missing from her family's holiday apartment at the Ocean Club, in Praia da Luz, on 3 May, 2007.She was holidaying with her parents and her younger twin siblings.
Mrs McCann is understood to have told police that after tucking the children up in bed Madeleine - who was wearing pink pyjamas with the words "Sleepy Eeyore" on them - said: "Mummy, I've had the best day ever. I'm having lots and lots of fun."
It is known Mr and Mrs McCann then went for dinner with a group of friends, at a tapas restaurant 100 yards from the apartment.
Their party - since dubbed the "tapas seven" - included fellow medics Matthew Oldfield, Russell O'Brien, David Payne and Fiona Payne.
Also present were Rachael Oldfield (married to Matthew), Jane Tanner (partner of Russell O'Brien) and Diane Webster (Fiona Payne's mother).
Leaks from the investigation suggest the McCanns arrived for dinner at 2035 local time that evening, according to their friends.
At 2105 Mr McCann went to check on the children, followed by Dr Oldfield, they said.
Ten minutes later, having left the table to check on her own children, Jane Tanner says she saw a man carrying a child, close to the McCanns' apartment
At 2200 Kate McCann checked on her children.
Madeleine was gone.
Mrs McCann told police that when she went to the apartment she found the outside shutter and window to Madeleine's room had been opened and her daughter was missing.
Mrs McCann said police were called within 10 minutes of finding her daughter gone.
Guilhermino Encarnacao, director of the judicial police in the Faro region, said officers arrived within 10 minutes of being alerted, and an investigation unit began work within 30 minutes
The manager of the Mark Warner resort in Portugal, John Hill, said about 60 staff and guests at the complex searched until daybreak for the little girl, while police notified border police, Spanish police and airports.
They were joined in their hunt by hundreds of volunteers in the following days.
The investigation
3 May, 2007: Three-year-old Madeleine McCann goes missing from her family's apartment in Praia da Luz.5 May: As the search for Madeleine continues, her parents issue a statement to say they "cannot describe the anguish and despair" they are feeling at their daughter's disappearance.
12 May: Mr and Mrs McCann make a fresh appeal for help on their daughter's fourth birthday.
15 May: British-born Robert Murat is made an official suspect - or "arguido" - following a search of his mother's villa. Casa Liliana is 150 yards from the apartment where Madeleine went missing.
26 May: A description of a man seen on the night Madeleine went missing "carrying a child or an object that could have been taken as a child" is issued by police.
30 May: The McCanns meet the Pope at a general audience in Rome at the start of a "European tour" to raise awareness of Madeleine's disappearance.
6 June: A German reporter asks the McCanns how they feel about the fact that "more and more people seem to be pointing the finger" at them, during a press conference in Berlin.
12 June: Mr and Mrs McCann arrive back in Portugal following their European tour.
17 June: Chief Inspector Olegario Sousa admits vital forensic clues may have been destroyed in the hours after Madeleine's disappearance, as the scene was not protected properly.
10 July: Formal suspect Robert Murat re-questioned
Late July: British sniffer dogs fly out to Portugal. Keela, who can detect minute quantities of blood, and Eddie, who is trained to detect dead bodies, work in the apartment and several cars, including the hire car the McCanns rented 25 days after Madeleine disappeared.
6 August: Police fail to find any new evidence after a search at the home of Mr Murat following a two-day search, the BBC understands.
7 August: Forensic tests are carried out in a Birmingham lab on suspected traces of blood found by sniffer dogs in Madeleine's apartment.
11 August: Police in Portugal acknowledge for the first time that, in light of new evidence, Madeleine may be dead. Chief Inspector Sousa adds that Mr and Mrs McCann are not being considered as suspects following newspaper speculation that they are under suspicion.
24 August: Police say they still have doubts over how Madeleine disappeared and whether she will ever be found.
31 August: The McCanns launch a libel action against Portuguese newspaper Tal & Qual which claimed "police believe" they killed their daughter. The McCanns say they are "deeply hurt" by the allegations.
6 September: Portuguese police interview Kate McCann for 11 hours as a witness in the presence of her lawyer. Separately, Portuguese detectives confirm they have the partial results of forensic tests by a UK laboratory.
7 September: Madeleine's mother is declared an official suspect and fears she could be charged, friends say. Gerry McCann is also named as a formal suspect following more questioning. Later, a family representative says officers believe they have found traces of Madeleine's blood in the McCanns' car, hired 25 days after she vanished.
9 September: Kate and Gerry McCann return home to Rothley, Leicestershire.
10 September: Police papers detailing the inquiry into Madeleine's disappearance are passed to Algarve-based prosecutor, Jose Cunha de Magalhaes e Meneses. In Leicestershire, police and social services meet to discuss the case.
11 September: In his internet blog, Gerry McCann says he and his wife Kate face an "unbearable" situation.
Portuguese police play down reports that DNA evidence with a 100% match to Madeleine was found in her parents' hire car.
A statement is made outside the prosecutor's office in Portimao, saying he had received the files detailing the inquiry into Madeleine's disappearance and decided they should go before an instructional judge.
The judge has 10 days to make a decision on the files' contents.
19 September: Portuguese prosecutors rule there is "no new evidence" in police files to justify re-questioning Gerry and Kate McCann.
9 October: A new police chief is appointed to take over the Portuguese inquiry.
Paulo Rebelo, deputy national director of Portuguese police, replaces Goncalo Amaral, who was removed apparently for criticising UK police. New police chief for McCann case
30 October: The fighting fund set up to find Madeleine was used to pay the McCanns' mortgage, it is disclosed.
1 November: Gerry McCann returns to work, as a consultant cardiologist, two days before the six-month anniversary of his daughter's disappearance.
26 September: A photograph taken by a Spanish tourist in Morocco is examined by experts, amid suggestions a girl in the picture could be Madeleine. Reporters later claim that the girl is in fact a Moroccan five-year-old.
16 November: Jane Tanner, one of the "tapas seven", tells the BBC's Panorama programme she saw a man carrying a child 45 minutes before Madeleine was discovered missing.
18 November: Gerry McCann, in a personal video, speaks of his belief that his family was watched by "a predator" in the days before his daughter's disappearance.
22 December: Kate and Gerry McCann send a Christmas message to Madeleine in a video appeal for information.
20 January, 2008: The parents of Madeleine McCann release sketches of a man they believe may have abducted their daughter.
The drawings are based on a description by a British holidaymaker of a "creepy man" seen at the resort.
19 March: The Express Newspaper group pays the Find Madeleine campaign £550,000 and publishes apologises to the McCanns for suggesting they were responsible for her death.
7 April: Portuguese police fly to the UK to sit in on interviews conducted by Leicestershire Police of the so-called "tapas seven".
8 April: Kate and Gerry McCann are asked by Portuguese police to take part in a reconstruction of the night their daughter disappeared.
10 April: Kate and Gerry McCann address the European Parliament in Brussels, calling for an EU-wide alert system for abducted children.
13 April: It is revealed Robert Murat, who along with the McCanns was also an official suspect in the case, is to sue some British-based newspapers over allegedly libellous stories.
14 April: Portuguese police deny leaking details of statements given by the McCanns early in the investigation.
Spanish television broadcasts quotes, including some made by Mrs McCann, supposedly telling officers that Madeleine had been upset the night before she disappeared that her mother had not come to her when she cried.
Late April: In the run-up to the first anniversary of Madeleine's disappearance the McCanns give a series of television and radio interviews and speak of their year of "purgatory".
2 May: The parents of Madeleine McCann urge anyone who spoke to police about her disappearance to contact them.
3 May: Kate McCann asks churchgoers to pray for her daughter on the first anniversary of her disappearance.
7 May: The Portuguese police chief criticised for his handling of the Madeleine McCann case has resigned, says the Ministry of Justice.
14 May: A judge overseeing the Madeleine McCann investigation extends judicial secrecy in the case.
27 May: A reconstruction of the night Madeleine McCann disappeared will not go ahead after the "tapas seven" declined to take part.
23 June: Madeleine McCann's parents take to the High Court an attempt to get police files on their daughter released.
1 July: Portugal's attorney general Fernando Pinto Monteiro says no decision has been taken on the Madeleine McCann investigation, after local media report that police will close it owing to lack of evidence.
But Portuguese police have submitted their final report on the case, which the attorney general says "will be the object of careful analysis and consideration".
7 July: Leicestershire police agree to release files on the case to Mr and Mrs McCann, who had earlier dropped a High Court bid to force the release of evidence.
15 July: British expat Robert Murat accepts a £600,000 damages settlement over allegations in 11 UK newspapers that he was involved in the disappearance of Madeleine McCann.
21 July: Portugal's attorney general Fernando Jose Pinto Monteiro announces that the police investigation into her disappearance will be shelved. All three suspects have their "arguido" status lifted.
After the official investigation
23 September 2009: Madeleine's parents return to Portugal together for the first time in more than two years. They meet lawyers and a PR agency in Lisbon to discuss ways to advance the search, but do not visit the resort where they last saw their daughter.A Portuguese judge grants an injunction temporarily banning sales and further publication of a book by former police detective Goncalo Amaral, Maddie: The Truth about the Lie, which was originally published in July 2008. Mr Amaral had been removed as head of the investigation into Madeleine's disappearance after criticising the involvement of British police.
21 October: Shirts emblazoned with pictures of Madeleine are handed out ahead of Everton FC's Europa League tie with Portuguese team Benfica in Lisbon. The words "We're Still Looking For You" are printed on them.
3 November: A one-minute video message - produced in seven languages - is launched by Britain's Child Exploitation and Online Protection Centre, showing new images of how the girl might look more than two years older.
13 December: Gerry and Kate McCann return to Praia da Luz, the resort they were staying at when Madeleine disappeared, while visiting Portugal for a court case over a book claiming she is dead.
28 January, 2010: A video of the McCann's search for Madeleine is shown at a fund-raising event in London in January to mark the 1,000th day since Madeleine's disappearance.
February: The Portuguese former detective fails to overturn a ban on his book about Madeleine. Gerry McCann says new information was not being followed up by Portuguese police.
28 April: Near the third anniversary of Madeleine's disappearance, Gerry McCann says it is "incredibly frustrating" that police in Portugal and the UK had not been actively looking for Madeleine "for a very long time".
6 March: The McCanns criticise the release of previously unseen Portuguese police files on their daughter's case to British newspapers. The 2,000-page dossier details dozens of possible sightings of Madeleine since she disappeared.
2 May: The McCanns release a video online which shows the couple trying to find their missing child over the past three years. It was originally shown in January.
May: The McCanns back the Child Rescue Alert (CRA) scheme in the UK and want Europe-wide co-ordination.
August: Kate and Gerry McCann hold private talks with Home Secretary Theresa May.
October: A court in Lisbon overturns a ban on the book Goncalo Amaral in which he questioned the couple's accounts of their daughter's disappearance.
November: The McCanns sign a publishing deal to write a book about their daughter's disappearance. They also launch a petition calling for a full review of the case by the UK and Portugal.
3 May, 2011: The McCanns mark the fourth anniversary of Madeleine's disappearance with family and friends.
12 May: In an open letter in the Sun newspaper, the McCanns ask the prime minister to launch an "independent, transparent and comprehensive" review of all information relating to the disappearance of their daughter.
They publish a book, entitled Madeleine, which the couple hope will prompt people holding vital information about what happened to Madeleine to come forward.
Sale proceeds will go towards the Find Madeleine fund.
13 May: Prime Minister David Cameron writes to the McCanns telling them the home secretary will be in touch to set out "new action" involving the Metropolitan Police.
http://www.bbc.co.uk/news/mobile/uk-13386785
