The brutal attacks in Paris on Friday have left Europe and the world asking the question of what can be done to prevent further violence.
France, in particular, has been targeted this year, first with the deaths of 12 people at the offices of the satirical Charlie Hebdo magazine in January. One of the perpetrators of that attack was later killed by police at a kosher supermarket after killing four more. In June, a manager was beheaded by an employee at a chemical plant in Lyon.
But it's not the first time France has handled dangerous terrorists. Between left-wing radicals and separatist movements, European authorities have battled terrorists — foreign factions and homegrown — for decades.