Sixteen agonising years may have passed, but Kate and Gerry McCann understandably cling onto a glimmer of hope that their daughter Madeleine could still be alive.
Their beloved eldest daughter Maddie vanished from their holiday apartment in Pria Da Luz on May 3, 2007.
The parents went out for dinner to a nearby restaurant with three other couples, only to return at 10pm to find their three-year-old missing from her bed.
Ever since, they have campaigned to keep the search alive for their little girl, who would now be 20 years old.
In the latest breakthrough, police search teams are scouring a remote reservoir that has been described as a "little paradise" by German paedophile Christian Brueckner, 45 - the prime suspect.
And Kate and Gerry have never stopped fighting to find out what happened to their first born, who seemingly went missing without a trace.
In the years since, the couple, who met in 1993 in Glasgow and married five years later, have had to find a way to put one foot in front of the other for the sake of their twins, Amelie and Sean, now 18.
Kate and Gerry, who still live in Rothley, Leicestershire, are devout Catholics, however Kate admitted her faith has been put to the test amid the trauma their family has faced.
In an extract from her 2011 book, Madeleine, Kate said: "There have been many times when I've felt God has deserted me or that He has let Madeleine down. I've occasionally doubted His existence altogether. And yes, I've been angry with Him..."
"For now, though, at least, my anger towards God seems to have subsided. I believe in Him and I still feel His presence."
The mum-of-three also stressed she believed "wherever Madeleine is, God is with her".
The grief would also test most marriages, but Kate and Gerry have stayed together for 25 years. However, Kate admitted it wasn't easy, explaining that her desire for intimacy "plummeted to zero" after Maddie went missing.
In her memoir, she wrote: "The first was my inability to permit myself any pleasure, whether it be reading a book or making love to my husband.
"The second stemmed from the revulsion stirred up by my fear that Madeleine had suffered the worst fate we could imagine: falling into the hands of a paedophile."
She went on to say that the thought of sex "repulsed" her after being "tortured" by such horrifying images.
"I worried about Gerry and me. I worried that if I didn't get our sex life on track our whole relationship would break down," she added.
But she went on to credit her husband's understanding for the endurance of their long-term partnership.
Not knowing what happened to her daughter placed a huge burden on her mental health, so Kate, who received her degree in medicine at the University of Dundee, quit her job as a GP.
However in 2021, it was reported that she had returned to the NHS frontline in a time of crisis against Covid.
She reportedly worked as a doctor in hospitals in Leicester and was said to be pleased to be "doing her little bit to help" as the city battled with soaring hospital admissions.
A pal told the Sun: "Kate's back working as a doctor. She's helping out at her local hospitals now and not doing any surgery work.
"She has thrown herself back into a full time job to assist others in need. There's such a demand for qualified medics during these unprecedented times."
Gerry, a cardiologist who is also a research professor at the University of Leicester, was said to be working in the same hospital at times, although they were "hardly ever" expected to come across each other due to the busy nature of their prestigious jobs.
Recently, Madeleine's sister Amelie joined her parents and well-wishes for an anniversary event 16 years on from the disappearance.
"It's nice that everyone is here together but it's a sad occasion," she said at the event.
Student Amelie lit a candle for her big sister and other missing children at the memorial, where pictures of Maddie adorned the black railing.
She was then accompanied by her friend in repeating mantras read out by people in the 70-strong crowd, including "Never never give up", "leave no stone unturned", "don't forget about me" and "still missing, still missed".
Amelie is said to be in the process of applying to university, but inevitably the absence of their sister has left a dark cloud over the lives of her and her brother.
In an interview with The Sun, Kate said Sean and Amelie have "grown up essentially without Madeleine but knowing their sister is missing and they want her back."
Kate previously told the Mirror ahead of her book launch that her twins gave her the strength to fight on, with Sean promising: 'When you're old, me and Amelie will look for Madeleine'.
She then revealed: "I was chatting to Amelie and she said, 'Mummy's sad because Madeleine is not here. But Amelie is here, and Amelie and Sean will always be here.'"
Keeping busy is the family's way of coping, though it will never fill the void left by Maddie's absence.
Speaking in her ambassador role for charity Missing People, Kate said about the twin teens: "They have their own friends and they keep busy and they're really sporty but their only wish is for their big sister to come home. We miss our complete family of five.
"As a family 98 per cent of the time we're busy. I don't know if that's a conscious thing but it helps.
"The urge to look for Madeleine absolutely hasn't changed at all."
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