Madeleine McCann was just three years old when she disappeared in 2007.
The toddler was holidaying with her family in Portugal when she went missing, while her parents were dining at a nearby restaurant.
There has never been a credible sighting of her since.
At around 10.00pm on May 3, 2007, British doctor and mum-of-three Kate McCann left a local tapas bar and walked the 83 metres back to her holiday apartment to check on her sleeping children.
The Disappearance of Madeleine McCann trailer. Post continues after video.
Kate, her husband Gerry, their three-year-old daughter Madeleine, and their two-year-old twins Sean and Amelia, had travelled to the area from Leicester, England, for a family holiday.
When Kate arrived at apartment 5A she immediately felt that something wasn’t right.
The door to the children’s room was further open than she had left it. When she looked in the room she saw Madeleine’s bed was empty. A gust of wind then blew into the room, revealing the open window and window shutters on the wall opposite Maddie’s bed.
Kate ran back to the tapas bar to where Gerry was dining with the seven friends they had travelled with, the group that would later become known as the Tapas 7.
She screamed: “They’ve taken her”.
The group quickly began searching the apartment and the surrounding area but there was no sign of Maddie. The McCanns then reported the toddler as missing.
In the following days, Portuguese, British and international press flocked to the seaside village. The story of the disappearance of a blonde-haired toddler in what was considered to be a safe family holiday hot spot was splashed across newspapers around the globe. It became one of the most sensationalised stories of the 21st century.
For the past 11 years Portuguese police, Scotland Yard, and Maddie’s parents have worked tirelessly trying to figure out what happened to the young girl. But so far, they have no answers.
Here are all the theories about what happened to Madeleine McCann:
The sex trafficking theory
One of the most prominent theories is that Madeleine was snatched by a sex trafficking network.
The Netflix documentary, The Disappearance of Madeleine McCann, looked at this theory in depth. It’s believed that Madeleine, a young white girl from a wealthy family, would have been a valuable target for child sex traffickers.