It was once a face you saw everywhere. The image of a blonde-haired, hazel-eyed little girl with a distinctive smudge on the iris of her right eye could be found in airports, gyms and movie screens.
Everyone knew Madeleine's McCann's name, her age, where she was from and where she went missing.
What they didn't know, what her family and authorities were desperate to discover, was what happened to her on the night of May 3, 2007.
In the week before she disappeared, the McCann family had embarked on a family trip to Portugal's Algarve coast. The picturesque location offered the perfect backdrop for a vacation filled with sun, laughter and friends.
But the illusion of tranquillity and security was shattered in an instant, when the McCanns' three-year-old daughter Madeleine vanished from her bedroom without a trace.
A 15-year search for answers has unearthed false leads, questionable science and spurious claims.
It has also brought the glare of international media to the close-knit community of Rothley in Leicestershire, England, where the McCanns live.
It was here, in Madeleine's hometown, where her disappearance was keenly felt by residents. Many laid flowers, brought teddy bears and tied yellow ribbons around trees in the days, weeks and months after she vanished.
"Talking to parents, it's had a long-term effect on them," said Joan Palmer, who has lived in the area for decades.
She remembers how the village rallied together after Madeleine's disappearance, holding special prayer meetings to show their support.
"It's really quite difficult to comprehend. I know the McCanns want closure, but they also live in hope that something will be coming to fruition," she told the ABC.
To this day, what happened to Madeleine and who might have been responsible is still unknown. No-one has ever been charged.
And as the anniversary of the day she went missing passes, a statute of limitations in Portugal may mean any chance for justice rests on one potential suspect.
Without a confession or a new discovery, the most famous missing persons case in the world may forever remain a mystery.
May 3, 2007
As the McCanns gathered to enjoy a final meal with other couples at the Praia da Luz resort where their three kids slept, they were unaware of how their lives were about to change forever.
The group of friends — who became known as the Tapas Seven — took turns checking on their children. At 9:05pm, Gerry McCann peeked into his children's bedroom and found all three of them sleeping soundly.
Fifty-five minutes later, as Kate McCann went to perform a similar check, she discovered her twins still sleeping in their little cot. The bed next to them, however, was empty.
A blanket and cuddly toy were all that remained in the place where her daughter once slept.
As patrons dined at the restaurant near the apartment, a heartbreaking wail pierced the idyllic atmosphere of the resort.
"Never in my life have I heard a cry like that," waiter Jeronimo Salcedas told police. It would mark the beginning of the McCann family's nightmare and a series of unanswered questions.
Where did their little girl go? Was she taken? Who took her? Would they find her?
Multiple searches of the area turned up nothing. Local police concluded Madeleine was likely kidnapped, though the early investigation produced no major leads.
Even so, journalists had flooded into the small town of Praia da Luz from all over the globe and the media frenzy around the case reached a fever pitch.
Fame is a double-edged sword
When Madeleine McCann's case made front page news, social media platforms were in their infancy.
Facebook and Twitter had just launched, in 2004 and 2007 respectively, providing new ways for Madeleine's story to reach audiences around the world.
Her disappearance coincided with the birth of the internet age "when news travels so quickly", according to Robbyn Swan, investigative journalist and co-author of the book, Looking for Madeleine.
"I think what happened initially is that the case was so relatable — a beautiful little [child] with telegenic, well-spoken parents capable of putting their story out there," Ms Swan told the ABC.
Even the McCanns' hometown could not escape the publicity of the case.
The small English village of Rothley was put "on the map, probably for all the wrong reasons", Ms Palmer said.
"If we [went] anywhere, I would say we live in Rothley and people [would] instantly make the connection or if you mentioned Madeline, 'oh yes, we remember that'," she said.
It was Gerry McCann himself who had ignited the media blitz that would eventually consume the couple.
"Please come forward, return Madeleine, leave her in a place of safety," he begged in a press conference just two days after his daughter disappeared.
The world was transfixed. But for all the good publicity the news around Madeleine attracted, it also had a negative impact.
Dr Xanthé Mallett, an anthropologist and criminologist, was working at a Scottish forensic centre in 2007 when Madeleine McCann went missing.
"We were having a discussion about the parents and their behaviour, body language, eye contact and their use of Maddie's name," she said.
"Everything was spot on for them telling the truth, for them having had nothing to do with it. And my opinion of that never changed."
Four months after Madeleine disappeared, Portuguese police brought in a blood hound and cadaver dog to investigate the apartment and a car hired by the McCanns.
The dogs alerted their handler 13 times to the scent of blood and death inside both places, according to a Portuguese police report.
That same month, a knock on the door of the McCanns' villa in Praia da Luz delivered another blow: Kate and Gerry were now considered arguidos — Portuguese for formal suspects.
Problems in the initial investigation
In Searching for Madeleine, Anthony Summers and Robbyn Swan conclude "the discoveries the British sniffer dogs had apparently made utterly changed the direction of the investigation".
"Had the dogs not been brought in, it is fair to say, there would have been no Portuguese police decision formally to declare Madeleine's parents suspects," they wrote.
The dogs, Eddie and Keela, were considered so good at sniffing out signs of foul play that their handlers charged authorities $617 a day to use them.
But Dr Mallett, who now works at the University of Newcastle, said Portuguese police "went down a rabbit hole" and relied too heavily on the dogs' signals.
"Cadaver dogs have a really fantastic utility. When you're looking for buried remains or remains that have been left on the surface for an extended period, they can really help narrow search areas," she said.
"They have to be used intelligently and in the context of the investigation and they can't be the only resource that you're employing."
A Portuguese police chief also admitted in 2007 that vital forensic clues may have been destroyed in the hours after Madeleine's disappearance, as the scene was not protected properly.
One of the problems from the outset was that police thought they were dealing with a child who wandered off and handled it that way, Ms Swan said.
"They didn't think they were dealing with a crime or a crime scene. And so they didn't preserve the crime scene in the way they should have done," she said.
That resulted in the loss of what police refer to as the "golden hour", Ms Swan said, which is the first 24 to 48 hours of a child abduction investigation that are considered critical to a successful outcome.
While the McCanns were cleared of any involvement by July the following year, the damage was done.
Without fresh leads, the investigation eventually stalled. Portugal's attorney-general shelved the McCann case in 2008 after declaring all existing avenues of investigation had been exhausted.
The McCanns, however, never stopped searching for their daughter.
In 2011, they asked then-British prime minister David Cameron to launch an "independent, transparent and comprehensive" review of all information relating to the disappearance of their daughter.
Two years later, Scotland Yard revealed it had "new evidence and new witnesses" in the case and was opening a formal investigation into the girl's disappearance.
Soon police released what they described as a "new understanding of events" on the night Madeleine went missing.
The dark reality of the perfect holiday hotspot
Praia da Luz is a quaint coastal town in Portugal's southern Algarve, sometimes dubbed Little Britain in a nod to its popularity among English families.
The centuries-old fishing village underwent a dramatic transformation in the 1990s as fields of barley and wheat were replaced with villas and apartment blocks.
New rentals, a sandy beach and picturesque cliffs soon attracted Northern Europeans and British tourists in search of a relaxing vacation.
But the McCann family's false sense of security at their Portuguese resort may have put Madeleine in the crosshairs of either human traffickers or a kidnapper working alone.
"A frightening truth about beautiful, sunny holiday areas — where parents let their guard down — is that those are very productive hunting grounds, let's call them, for paeodophiles," Ms Swan said.
"That's something we've seen repeatedly in this case. The number of names with predatory sexual histories against children that were in the Algarve at around the time Madeline disappeared, is pretty horrifying."
A British police unit set up to investigate the case uncovered nine sexual assaults and three "near misses" on British girls aged between six and 12 who were on holiday in the Algarve region between 2004 and 2006.
Amid some witness reports of a "suspicious blond-haired man" loitering near the Ocean Club resort in the days before she vanished, police acknowledged it may have been a "pre-planned abduction".
But on the night Madeleine McCann vanished, police assumed she had left the apartment of her own accord and would be found soon enough.
Kate McCann said it took 12 hours for authorities to put up roadblocks.
And with Portugal's easy access to Spain and Morocco, 12 hours would have been more than enough time to spirit a child out of the country.
"It does appear most likely that she was taken by a stranger, possibly somebody who had stalked her or perhaps had been watching the family and knew that they sometimes left the kids to go and have something to eat," Dr Mallett said.
"That's in no way a criticism because I think families do that kind of thing all the time. And 99.9 per cent of the time, it's fine.
"But unfortunately, I think this time, they were perhaps being stalked by a predator."
A surprising discovery
After years of stale leads and false alarms, an unexpected breakthrough came in 2020.
German police declared they had zeroed in on the likely culprit.
The man, who cannot be named for legal reasons, arrived in the Algarve in the mid-1990s, before going on to commit a string of crimes there.
For several of those years, he lived in a house between Lagos and Praia da Luz, where Madeleine disappeared.
He is currently behind bars in Germany for raping a woman in the Algarve.
A phone attributed to the man placed him in the area where Madeleine went missing within a 30-minute window, an expert told the BBC.
The man has not been charged with any crime related to Madeleine's disappearance and denies any involvement.
Few other details have been released about the suspect, and with no progress for several years, it appeared as if the case would go cold once again.
But late last month, there was yet another twist.
Portuguese prosecutors identified the German man as a formal suspect in their local investigation.
It does not appear that they had any new evidence against him, and some experts speculate it was a doomed attempt to stop the clock on Portugal's statute of limitations.
"In a legal point of view, if you cannot find anybody [under] official suspicion … during a 15-year period of time … that means that investigation cannot proceed," Lisbon-based lawyer Rogério Alves said.
In Portugal, that statute is in place for crimes with a maximum prison sentence of 10 years or more, including kidnapping or murder.
After May 3, it will no longer be possible to declare someone a person of interest.
Even if somebody confessed or new evidence came to light that related to a crime committed on the day Madeleine went missing, this person could not be prosecuted.
"The legal period has been fulfilled," Mr Alves said, for all crimes committed on May 3, 2007.
If the crime was ongoing, however, the statute of limitations would not be an issue, another Portugese lawyer suggested.
Spencer Dohner from MDM Legal in Portugal said if new evidence emerged that proved further crimes were committed against Madeleine after May 3, the police have more time to act.
"If it was an ongoing matter … then the clock will [stop] only after that ongoing act terminates," Mr Dohner said.
Is there any hope left for the McCann family?
There are currently three separate investigations — British, German and Portuguese — into the McCann case.
Mr Alves said the Portuguese investigation rests on whether local authorities have more information on the suspect than what they have publicly discussed.
"The first question is, why did he became an arguido?" Mr Alves said.
"There must be some reason … so now the police will have to investigate how deep can they go, trying to find evidence against him."
After all the lines of investigation are finished, Mr Alves said, authorities will have to make a decision of whether to charge him or not.
If he isn't charged, this does not mean the case is closed, according to Mr Dohner, who argued there are "other possibilities on the table".
"Imagine that [Madeleine] was discovered in 20 years' time, alive. This is not closed," he said.
As for the German investigation, authorities are uncertain when they will be able to make further announcements about their progress.
"We can't say whether we'll come to a conclusion this year or next year," Hans Christian Wolters, the German prosecutor in charge of the case, said.
Under European Union laws, the German man could be prosecuted in his home country for crimes he allegedly committed in other parts of the EU.
In Germany there is no statute of limitations for serious crimes like murder.
While McCann's parents are being kept informed of developments, they are still left waiting for answers, 15 years later.
"I hope those answers are still out there," Dr Mallett said.
"And that one day they do find out what happened to Maddie, who was responsible and ultimately they get her back."
In the meantime, though the possibility may be slim, Kate and Gerry McCann say they "have not given up hope that Madeleine is still alive" and that they will be reunited with her.
