Belgium has the highest number of foreign fighters who've joined ISIL
Belgium is known for its chocolate and beer, but it is now also becoming infamous as a recruiting ground for terrorism.
Molenbeek, a rundown district in Brussels, has become a hotbed for radicalism following the Paris terror attacks. Belgium has the highest number of foreign fighters who've joined the so-called Islamic State. Dozens have roots in Molenbeek.
The mayor of Molenbeek said the area has high unemployment and jihadist recruiters target young men who have few prospects and are susceptible to ISIL's message: "They were also thugs, delinquents, ordinary delinquents but some of them had also been to jail. And after they have been, I would say, infected by jihadism, infected by this violent radicalization, by this terrorism. And so I'd say there are several factors which explain why some youth from here became jihadists."
The ring leader of the Paris attacks, Abdelhamid Abaaoud, and three other attackers grew up in Molenbeek.
The presence of a terrorist den in the heart of Brussels is a reminder that the pipeline of foreign fighters from Europe to Syria, flows both ways. Experts say major changes need to be made in the way intelligence agencies track jihadists returning from Syria:
"The European intelligence relies too much on technology - satellites, phone tapping, etc. Which are wonderful toys for spies. But it will not give you an insight. It will not give you a human source. To get the human source you need to have a human officer on the field. And it's only the human source who will tell you 'this man is dangerous and tomorrow he will attack somewhere in Brussels or in Paris'."
Read also Pope Francis condemns Brussels attackers
Police are still searching for suspects with links to the Brussels attacks, but bringing those responsible to justice may do little to stop further radicalization.