It's sad but I don't think it's strange at all - children are taken, children go missing, all over the world, and many of them are never heard of again. This one was so high profile becase her parents could afford for it to be so - and they must feel so guilty for leaving the children alone in the apartment whilst they were eating. Small pretty blonde girl - one theory is that a fast boat was waiting and she was in North Africa within a few hours. There have been alleged sightings all over Europe. BTW, her mother was adamant that they never called her Maddie, the press abbreviated it, she was always called Madeleine.
You may also remember the little blond boy who went missing in Cyprus, that must be twenty years ago now, he was never found either.