Balkan is the biggest security hole in Europe, which was recognized and by terrorists, because most of the arms that they are using is coming from the region, according to the Vienna daily "Kronen Zeitung". List indicates that the assassins in Paris used a weapon that is originating from the Balkans, where currently, according to estimates, there are four million unregistered weapons on the black market. For decades, criminals of all kinds, use Balkan route as a "criminal highway" to and from Europe. According to Europol, more than four million weapons from the wars in the former Yugoslavia are in circulation in the Balkan countries. "Relatively is easy to get to these weapons. The gangs have specialized in arms trade. The smuggling takes place over the same routes over which the drug reaches Russia and Europe," said an unnamed UN expert. In addition to that boundaries are disappearing between "normal" crime and terror. "From Afghanistan through the Balkans, to EU annually enters heroin worth about 17 billion euros. Profit from the deal goes into the pockets of Al Qaeda," experts said. Also, the financing of radical persons in Europe goes through the Balkans. "Money mainly goes to Austria and Liechtenstein, where is being washed and then it can be used without problems," said an unnamed expert in a statement to Vienna daily.